Lack of correlation between haemodynamic and cardiopulmonary exercise capacity improvement after catheter-balloon mitral valvuloplasty

The long-term effects of percutaneous transvenous mitral commissurotomyon exercise capacity and ventilation were investigated to determinewhether a dissociation between haemodynamic improvement andexercise capacity increase occurs in patients with mitral stenosis.Eighteen patients aged 45 ± 12.3 years (mean ±SD) with symptomatic mitral stenosis performed a symptom-limitedbicycle exercise test while respiratory gases were measuredbefore and 6 months after percutaneous transvenous mitral commissurotomy.The mitral valve area increased from 1.07 ±0.22 to 1.98±0.67 cm². P<0.0001 and the mean mitral gradient decreasedfrom 12.9 ±4.5 to 5.3±4.8mmHg, P<0.001, withouta significant increase in cardiac output index (from 2.64 ±0.55 to 2.77 ± 0.56 l. min_{– 1}. m_{– 2}, P= ns).This haemodynamic improvement was still present at the 6-monthfollow-up catheterization. Mean exercise workload and peak oxygenuptake increased 6 months after percutaneous transvenous mitralcommissurotomy from 88.3 ± 28.1 to 97.8 ± 25.1watts, P= 0.01, and from 18.1 ± 5.3 to 19.9 ±4.8 ml. kg_{– 1}.min_{– 1}, P<0.05. Total ventilation,ventilatory equivalents and oxygen pulse at the end of the exercisetest remained unchanged Correlations between peak oxygen orexercise capacity improvement and mitral valve area increasewere poor (r= 0.27, P= ns, r= 0.24, P=ns). This clear dissociationbetween haemodynamic improvement and improvements in minor exercisecapacity after percutaneous transvenous mitral commissurotomysuggests that peripheral alterations persist. Future studiesin which patients are trained after valvuloplasty may be helpful.     

Peak oxygen uptake during exercise in mitral stenosis with sinus rhythm or atrial fibrillation: lack of correlation with valve area: A study in 70 patients

Although the haemodynamic response during submaximal supineexercise in mitral stenosis has been well described, the determinantsof peak oxygen uptake during maximal upright exercise are poorlycharacterized and may differ in sinus rhythm and atrial fibrillation.Seventy patients with isolated mitral stenosis underwent Doppler-echocardiographyand bicycle exercise with respiratory gas analysis. Forty-twopatients were in sinus rhythm (Group I) and 28 in atrial fibrillation(Group II). Peak oxygen uptake it was 21·3±5·6ml. min^–1 kg^–1 in group I and 18·1 ±5·1 ml min^–1 kg^–1 in group II (P<0·05).There was no significant correlation between indices of exercisetolerance (exercise duration, ventilatory threshold, peak oxygenuptake, indexed peak oxygen uptake, peak oxygen pulse) and valvearea or gradient in either group. Indexed peak oxygen uptakewas not correlated to oxygen pulse but was linearly related(r=0·43) to heart rate ( heart rate =peak heart rate=restheart rate) in Group I but not in Group II. Thus, in patientswith mitral stenosis, no correlation was found between the mitralvalve area or the gradient at rest and maximal upright exercisetolerance, suggesting that peripheral adaptation and, in sinusrhythm, chronotropic reserve, are important compensatory mechanisms.     

Exercise tolerance in patients with mitral stenosis before and after acute percutaneous mitral valvuloplasty: Role of lung diffusing capacity limitation?

The aim of this study was to specify in patients with tightmitral stenosis whether lung diffusing capacity could play arole in their exercise intolerance. A similar study was recentlycarried out in patients with moderate chronic heart failure. Ten patients with tight mitral stenosis were studied beforeand 6 months after successful percutaneous transvenous balloonvalvuloplasty and compared to six control subjects. Measurementsof diffusing capacity, evaluated by the lung transfer factor(TLCO) and by the transfer coefficient (TLCO/VA), obtained atrest and during early recovery after cardiopulmonary exercisetesting were performed. Cardiac output was determined non-invasively,both at rest and during exercise, using the carbon dioxide exponentialrebreathing technique. Prior to valvuloplasty, TLCO and TLCO/VA were not differentat rest between the two groups. During exercise, patients differedfrom control subjects, with lower oxygen uptake (P<0·00l)and lower cardiac output at peak exercise (P<000l). Thesevalues at peak exercise were significantly correlated (p=0·02;r=0·75). Moreover, patients differed from control subjectsat early recovery after peak exercise with an absence of increasein TLCO (P<0·05). Six months after valvuloplasty, a decrease of both TLCO (P<Oand TLCO/VA (P<0 was observed at rest. During exercise, comparisonof patients demonstrated a significant increase of both peakexercise oxygen uptake (SLVO P<0·0l) and cardiac output(P<0·00l). At early recovery after peak exercise therewas a significant increase in TLCO (P<O05) and TLCO/VA (P<0·01),such that a TLCO and a TLCO/VA appeared (P<0·05) identicalto that observed in control subjects. Moreover, SLVO₂ was significantlycorrelated in patients with Q+TLCO/VA (p=0·02; r=0·72). In conclusion, this study suggests a role, at least partial,of lung diffusing capacity in exercise intolerance in patientswith tight mitral stenosis and in the improvement of their aerobicexercise capacity demonstrated after successful percutaneousballoon valvuloplasty.     

Balloon mitral valvotomy: comparison between antegrade Inoue and retrograde non-transseptal techniques

AIMS: The results of percutaneous mitral valvotomy performed by theantegrade transseptal method using the Inoue balloon (n=1000;group 1) and by the retrograde non-transseptal technique usinga polyethylene balloon (n=100; group 2) were compared in a retrospective,non-randomized study. METHODS AND RESULTS: Both the groups were similar with respect to baseline characteristics.The success rate was 95% in group 1 and 93% in group 2. Therewas a significant increase in mitral valve area estimated byGorlin's equation (Group 1: from 0·8 ± 0·5to 2·1 ± 0·8 cm²; Group 2: from 0·8± 0·3 to 1·9 ± 0·8 cm², bothP<0·001) and by Doppler echocardiography using thepressure half-time method (Group 1: from 0·9 ±0·4 to 2·2 ± 0·6 cm²; Group 2: from0·9 ± 0·3 to 2·0 ± 0·7cm², both P<0·001). However, the calculated immediatepost-valvotomy mitral valve area was larger with the Inoue technique(2·1 ± 0·8 vs 1·9 ± 0·8cm²; P<0·02). Results were considered optimal whenthe mitral valve area increased to 1·5 cm², the percentageincrease was 50, and mitral regurgitation was 2/4. Out of thetotal successful procedures, optimal results were obtained in95% patients in Group 1 and 94% in Group 2. Incidence of significantmitral regurgitation (grade 3/4) was similar in two groups (Group1: 4% vs Group 2: 5%, P=ns). A significant left to right atrialshunt (Qp/Qs 1·5:1) in 2·5% and tamponade in2% of cases occurred exclusively with the Inoue technique, whileconduction disturbances, such as transient (<24 h) left bundlebranch block (28%) and complete heart block (2%) were notedwith the retrograde technique (Group 2). Local complicationswere significantly higher in Group 2 (3% vs 0·5%, P<0·01).The procedure time with the Inoue technique was shorter thanwith the retrograde (Group 1: 15 ± 8, range 10 to 35min; Group 2: 22 ± 14, range 15 to 45 min, P=0·05).Echocardiographic follow-up at 1 year showed no significantdifference in mitral valve area between the two groups (Group1 (n=300): 1·8 ± 0·8 vs Group 2 (n=60):1·9 ± 0·9 cm²; P=0·3). CONCLUSION: Balloon mitral valvotomy using the Inoue balloon and the retrogradenon-transseptal technique results in significant immediate haemodynamicand symptomatic improvement. The Inoue technique achieved alarger immediate post-valvotomy mitral valve area, but the differencewas not apparent at 1 year follow-up. Incidence of significantmitral regurgitation was similar with both the techniques; however,local complications occurred more frequently with the retrogradetechnique. Both techniques may complement each other in technicallydifficult cases.     

Physical responses to different modes of interval exercise in patients with chronic heart failure--application to exercise training

METHOD: In exercise training with chronic heart failure patients, workingmuscles should be stressed with high intensity stimuli withoutcausing cardiac overstraining. This is possible using intervalmethod exercise. In this study, three interval exercise modeswith different ratios of work/recovery phases (30/60 s, 15/60s and 10/60 s) and different work rates were compared duringcycle ergometer exercise in heart failure patients. Work ratefor the three interval modes was 50% (30/60 s), 70% (15/60 s)and 80% (10/60 s) of the maximum achieved during a steep ramptest (increments of 25 w/l0s) corresponding to 71, 98 and 111watts on average. Metabolic and cardiac responses to the threeinterval exercises were then examined including catecholaminelevels and perceived exertion. Parameters measured during intervalexercise were compared with an intensity level of 75% peak VO₂,determined during an ordinary ramp exercise test (incrementsof l2·5 W. min^–1). RESULTS: () (1) In all three interval modes, VO₂, ventilation and lactate did not increase significantlyduring the course of exercise. Mean values during the last workphase were between 754 ± 30 and 803 ± 46 ml. min^–1for VO₂, between 26 ± 3 and 28 ± 11. min^–1for ventilation and between 1·24 ±0·14and l·29 ± 0·10 mmol.1^–1 for lactate.(2) In mode 10/60 s, heart rate and systolic blood pressureincreased significantly (82 ± 485 ± 4 beats. min^–1;124 ± 5134 ± 5 mmHg; P<0·05 each), whilein mode 15/60 s catecholamines increased significantly (norepinephrine0·804 ± 0·0891·135 ± 0·094nmol. 1^–1; P<0·008; epinephrine 0·136± 0·012 0 193 ± 0·019 nmol. 1^–1;P<0·005). (3) In all three modes, rating of leg fatigueand dyspnoea increased significantly during exercise but remainedwithin the range of values considered ‘very light to fairlylight’ on the Borg scale. (4) Compared to an intensitylevel of 75% peak VO₂, work rate durrng interval work phaseswas between 143 and 221%, while cardiac stress (rate-pressureproduct) was significantly lower (83–88%). CONCLUSION: All three interval modes resulted in physical response in anacceptable range of values, and thus can be recommended.     

Simplified percutaneous mitral valvuloplasty with the Inoue balloon

Background Percutaneous mitral valvuloplasty with the Inoue balloon isconventionally performed with double vascular access: arterialand venous. However, in patients with a good echogenic windowit may be performed with venous access only and the proceduremonitored by 2D-echocardiography and colour flow mapping. Thisshould result in early ambulation and hospital discharge withreduced arterial complications. Aims To compare retrospectively the immediate results of percutaneousmitral valvuloplasty with the Inoue balloon in two groups ofpatients: Group I: venous access only (no arterial access, n=102)and Group II: conventional double vascular access (arterialand venous access, n=275). Methods and Results The baseline characteristics of the two groups were comparablefor age, sex, clinical, echo-cardiographic, radiological andhaemodynamic variables. The mitral valve area (Group I: 1·1±0·3to 1·85±0·5cm²vs Group II: 1·05±0·2to 1·85±0·5cm², P=ns) and transmitral gradient(Group I: 11±4 to 4·7±2mmHg vs Group II:12±4 to 4·8±2mmHg, P=ns) before and aftermitral valvuloplasty were not statistically different. A goodimmediate result, defined as mitral valve area >1·5cm²andmean mitral gradient <5mmHg with mitral regurgitation 2+at the end of the procedure, was observed in 77% of the casesin the venous-only group and 79% in the double access group(P=ns). The incidence of severe mitral regurgitation (GradeIII or IV) was not statistically significant. Procedural duration(71±24min vs 109±26min, P<0·01), fluoroscopictime (12·5±5·5min vs 18·5±6min,P<0·01) and hospital stay (2·8±15 daysvs 4·8±2·6 days, P<0·001) weresignificantly shorter in the venous-only group than in the conventionalInoue series. Conclusion Single venous access balloon mitral valvu-loplasty is as equallysafe and effective as double vascular access. The additionaladvantages of single venous access are shorter procedural duration,fluoroscopic time and hospital stay. We recommend that it beperformed by an experienced operator (minimum of 100 trans-septalpunctures) in patients without major thoracic deformity anda good echogenic window.     

Physical training improves exercise capacity in patients with mitral stenosis after balloon valvuloplasty

BACKGROUND: Haemodynamic measurements taken at rest and during exerciseshowed that percutaneous transvenous mitral commissurotomy resultsin both acute and long-term improvement. However, the time lagbefore there is an increase in exercise and in peak oxygen uptakeappears to be delayed and irregular. PATIENTS AND METHODS: To assess the potential of physical training to restore betterphysical capacity after percutaneous transvenous mitral commissurotomy,26 patients with mitral stenosis were studied after the procedure.The group was split into two. Thirteen underwent a 3-month rehabilitationprogramme, and the other 13, who did not, acted as controls. RESULTS: The mitral valve orifice area increased similarly, from 1·;12±017to 1·88 ±0·28 cm² in the training groupand from 1·04±0·16 to 1·88±0·19cm² in the control group. Cardiopulmonary parameters were similarbefore percutaneous transvenous mitral commissurotomy (peako₂: 19·9±2·4 vs 18·9±4·5ml. min^–1. kg^–1; peak workload: 94·6±29·3vs 96·1±25 watts; o₂ at anaerobic threshold: 17±3·4vs 16·1±5·2 ml. .min^–1. kg^–1;all P=ns). Three months later the results were higher in thetraining group (peak o₂: 26·6±4·7 vs 21·6±3·8ml. min^–1. kg^–1, P=0·001; peak workload:125·4±26·6 vs 108·5±23 watts,p=0·03; o₂ at anaerobic threshold: 19·6±5·8vs 15·8±2·9 ml. min^–1. kg^–1;P=0·02). CONCLUSION: These results indicate that patients should take up exerciseafter successful percutaneous transvenous mitral commissurotomyfor better functional improvement.     

Influence of aortic regurgitation on the assessment of the pressure half-time and derived mitral-valve area in patients with mitral stenosis

The influence of aortic regurgitation on the Doppler assessmentof pressure half-time (T) and on the derived calculation ofthe mitral-valve area has not yet been adequately evaluatedin patients with mitral stenosis and associated aortic regurgitation.Therefore this study was undertaken to verify the accuracy ofthe T method for the noninvasive estimation of mitral-valvearea in patients with mitral stenosis and associated aorticregurgitation. Data were obtained from 31 selected patientswho underwent cardiac catheterization within 24 h of the noninvasiveexamination. From the Doppler velocity curve, T was calculatedas the interval between the peak transmitral velocity and velocity/. Mitral-valve area was measured fromthe T with a computerized system using the equation: 220/T,in cm². Calculation of the mitral-valve area at catheterizationwas derived applying the modified Gorlin formula. Mean mitral-valvearea, as determined at catheterization, ranged from 0.5 to 2.8cm² (1.3±0.6). Mean mitral-valve area, as calculatedby continuous-wave Doppler, ranged from 0.7 to 2.7 cm² (1.5± 0.6). Linear-regression analysis of data revealed agood correlation between Gorlin and Doppler measurements ofthe mitral-valve area (r = 0.90, SEE = 0.28 cm², P<0.001,y = 1.0x + 0.2). Doppler showed a systematic overestimate ofthe mitral-valve area (26%) in patients with mitral stenosisand aortic regurgitation as compared to the Gorlin formula.The overestimate of continuous-wave Doppler was even greater(39%) in a subgroup of patients with 2 + or 3 + angiographicaortic regurgitation. Thus the Doppler T method still providesaccurate noninvasive estimates of mitral-valve area in patientswith mitral stenosis and associated aortic regurgitation. However,when the degree of aortic regurgitation is significant, Dopplercan lead to important overestimation of the mitral orifice size.     

Exercise training in heart failure improves quality of life and exercise capacity

Aims Benefit from exercise training in heart failure has mainly beenshown in men with ischaemic disease. We aimed to examine theeffects of exercise training in heart failure patients 75 yearsold of both sexes and with various aetiology. Methods and Results Fifty-four patients with stable mild-to-moderate heart failurewere randomized to exercise or control, and 49 completed thestudy (49% 65 years; 29% women; 24% non-ischaemic aetiology;training, n=22; controls, n=27). The exercise programme consistedof bicycle training at 80% of maximal intensity over a periodof 4 months.Improvements vs controls were found regarding maximalexercise capacity (6±12 vs –4±12% [mean±SD],P<0·01)and global quality-of-life (2 [1] vs 0 [1] units [median {inter-quartilerange}],P<0·01), but not regarding maximal oxygenconsumption or the dyspnoea–fatigue index. All of thesefour variables significantly improved in men with ischaemicaetiology compared with controls (n=11). However, none of thesevariables improved in women with ischaemic aetiology (n=5),or in patients with non-ischaemic aetiology (n=6). The trainingresponse was independent of age, left ventricular systolic function,and maximal oxygen consumption. No training-related adverseeffects were reported. Conclusion Supervised exercise training was safe and beneficial in heartfailure patients 75 years, especially in men with ischaemicaetiology. The effects of exercise training in women and patientswith non-ischaemic aetiology should be further examined.     

Assessment of accuracy of the Doppler pressure half-time method in the estimation of the mitral valve area immediately after balloon mitral valvuloplasty

AIM: The reliability of Doppler echocardiography in determining themitral valve area after balloon mitral valvuloplasty has beenquestioned, as discrepancies were noted between measurementsobtained by the pressure half-time method and those derivedhaemodynamically, immediately following completion of the procedure.Recent investigations, however, have indicated that these discrepanciesmay be attributable to the over-estimation of the mitral valvearea by haemodynamic measurements, caused by the presence ofthe iatrogenic atrial septal defect complicating transseptalcatheterization. The aim of the present study was to furthertest this hypothesis. METHODS AND RESULTS: Measurements of the mitral valve area by the Doppler pressurehalf-time method and the Gorlin formula were obtained and comparedin 238 consecutive patients before and immediately after retrogradenon-transseptal balloon mitral valvuloplasty, which does notinvolve puncture and/or dilatation of the inter-atrial septum.No significant difference was found between Doppler- and Gorlin-derivedmeasurements, neither before (1·04±0·23vs 1·03±0·23cm², P=ns) nor immediatelyafter (2·14±0·47 vs 2·12±0·49cm², P=ns) valvuloplasty. Linear regression analysis demonstrateda high degree of correlation between Doppler and Gorlin measurementsbefore (r=0·778) and after (r=0·886) the procedure.Good agreement was confirmed by the Bland—Altman method. CONCLUSION: Doppler echocardiography yields accurate measurements of themitral valve area immediately after retrograde non-transseptalballoon mitral valvuloplasty. This finding supports the hypothesisthat the creation of an iatrogenic atrial septal defect duringtransseptal catheterization may contribute to the poor agreementbetween Doppler and Gorlin data after balloon mitral valvuloplasty.     

Balloon aortic valvuloplasty in elderly patients at high risk for surgery, or inoperable: Immediate and mid-term results

Although aortic valve replacement is undoubtedly the treatmentof choice for aortic valve stenosis, balloon aortic valvuloplastymay represent the only possible treatment for some frail elderlypatients who may have additional medical problems. We evaluatedimmediate and 1-year results of balloon aortic valvuloplastyin 86 patients 80 years with severe aortic stenosis. Mean agewas 84±3 years. Forty-four % were 85 years or older.Mean gradient decreased from 68 to 26 mmHg and valve area increasedfrom 0•53 to 0•96 cm² (P<0•05). There weretwo per-procedural deaths. No local vascular complication wasobserved During the follow-up (13±9 months), 27 patientsdied, four had repeat balloon aortic valvuloplasty and eightunderwent aortic valve replacement. Persistent clinical improvementwas observed in 78% of the surviving patients. One-year actuarialsurvival rate was 73%. Balloon aortic valvuloplasty appearsto be a safe and valuable technique in cases where surgery cannotbe performed or carries a very high risk.     

Should mitral valve area assessment in patients with mitral stenosis be based on anatomical or on functional evaluation? A plea for 3D echocardiography as the new clinical standard.

This editorial refers to "Non-invasive assessment of mitralvalve area during percutaneous balloon mitral valvuloplasty:role of real-time 3D echocardiography" by J. Zamorano et al.on page 2086 In the last decade, 3D echocardiography has evolved from a researchtool to clinical utility in several cardiac applications. Oneof these is the accurate planimetry of native stenotic mitral^1–7and aortic⁸ valves and even mechanical prosthetic valves, bothin the mitral and aortic position.⁹ Percutaneous mitral valvuloplasty (PMV) has become the procedureof choice for treatment of selected patients with mitral stenosiswith     

Balloon occlusion during coronary angioplasty as a model of myocardial ischaemia: reproducibility of sequential inflations

In order to evaluate the potential of balloon occlusion duringcoronary angioplasty as a model of myocardial ischaemia in manwe have measured coronary sinus blood flow (CSBF), myocardialoxygen consumption (MVO₂), lactate extraction (LER) and electrocardiographicchanges in 11 patients undergoing left anterior descending artery(LAD) angioplasty. Baseline measurements were made before ballooncrossing and between inflations. Four consecutive inflationseach of 60 s duration were made; 5 min return to baseline wasallowed between inflations. There was a significant reduction in CSBF and MVO₂ (ml min^–1)during inflations 2, 3 and 4 (CSBF: 121±6694±53,113±4999±42, 124±66102±41, P<0.02;MVO₂:11.3±6.6–9.1±3.9, 10.4±3.7–8.7±2.4,12.2±4.49.4±2.8, P<0.05). However during thefirst period of balloon occlusion there were inconsistent changesin coronary flow with an overall rise in mean flow (97±35128±80ml min^–1, P = NS) and an overall rise in mean myocardialoxygen consumption (9.6 ± 3.812.5 ± 7.5 ml min^–1,P = NS). There was lactate production during all four inflationsbut the changes during the first one did not achieve statisticalsignificance. These inconsistent changes during the first inflation were thoughtto be due to partial obstruction of the stenosis by the deflatedballoon before primary dilatation. The changes due to crossingand during the first two inflations were further investigatedin another group of 12 patients undergoing LAD angioplasty.Great cardiac vein flow (GCVF), CSBF, MVO₂ and LER were recordedat baseline, during crossing and during the first two inflations.With the deflated balloon across the stenosis there were nochanges in CSBF or MVO₂ but there was a fall in GCVF (103±2877±50,P = NS) and a significant fall in LER (77±5716±37,P<0.01). Although there was a fall during the first inflationin CSBF, GCVF, MVO₂ and lactate extraction none of these changeswere significant. During the second inflation these changeswere of greater magnitude and achieved statistical significance. While balloon occlusion during coronary angioplasty has thepotential of providing a model of ischaemia in man we have foundthe first inflation period unreliable, due to the variable degreeof occlusion by the deflated balloon. We suggest that only subsequentinflations after the primary dilatation are used for observations.These findings are of significance when evaluating the effectsof therapeutic interventions during PTCA. Various refinementsin measurements of the effects of ischaemia will improve thespecificity of the model.     

Interpretative reproducibility of two-dimensional echocardiographic images. Analysis of intraobserver, interobserver and beat to beat reproducibility of the mitral value orifice

The intraobserver, interobserver and beat to beat interpretativereproducibility of two-dimensional echocardiographic imagesof the mitral valve area has been studied retrospectively ina group of 37 patients affected by rheumatic mitral valve disease.Reproducibility has been expressed either in terms of mean absoluteor percent error of duplicate measurements. A group of 11 normalsubjects was used for comparison. In our normal group the intraobserver, interobserver and beatto beat reproducibility averaged 1.8±2.1%, 3.1±1.4%,2.7±2.0% or 0.12± 0.14 cm², 0.21±0.10cm²,0.17±0.13 cm², respectively. In our patient populationthe intraobserver, interobserver and beat to beat reproducibilityaveraged 2.7±2.7%, 4.1±4.9%, 4.6± 3.6%or 0.05±0.05 cm², 0.08± 0.10cm², 0.08±0.06cm².In both groups there was no statistical difference among intraobserver,interobserver and beat to beat reproducibility either in termsof percent or absolute value. The mean percent error did not significantly differ betweennormal or stenotic valves or, in this latter group, among valvesof different sizes (1.4cm²; 1.5–2.4 cm²; 2.5 cm²). Themean absolute error, on the contrary, statistically differedbetween the two groups or among valves of different sizes, beinglarger in normals or in valves 1.5 cm². Thus, the interpretativereproducibility for two-dimensional echocardiographic imagesof the mitral valve area is small and acceptable for most clinicalpurposes. The use of mean percent error of duplicate measurementsmakes the quantification of reproducibility easily comprehensiblein clinical practice and insensitive to the actual cross sectionalarea of the structure examined thus allowing the data to beextended to cardiac structures of different sizes.     

Lipoprotein(a) as a risk predictor for cardiac mortality in patients with acute coronary syndromes

Aims Raised lipoprotein(a) concentrations are considered to be arisk factor for atherothrombotic diseases. We examined whetherbaseline concentrations were a risk factor for an adverse outcomein patients admitted with acute coronary syndromes. Methods and Results Five hundred and nineteen patients admitted with suspected acutecoronary syndromes were studied and followed prospectively fora median of 3 years. The prognostic significance of a baselinelipoprotein(a) concentration of 30mg.dl^–1or lower forsubsequent cardiac death was assessed in patients with myocardialinfarction (266) and unstable angina (197) and compared withother variables in regression models. In patients with myocardialinfarction, a baseline lipoprotein(a) concentration of 30mg.dl^–1wasassociated with a 62% increase in subsequent cardiac death comparedto the lower concentration group (29·8% vs 18·6%,Log rankP=0·04). In a multivariate regression model abaseline lipoprotein(a) concentration of 30mg.dl^–1retainedits significance as an independent predictor of cardiac death(P=0·037). In patients with unstable angina, baselineconcentrations of 7·9mg.dl^–1were found to be significantpredictors of cardiac death in univariate (P=0·021) andmultivariate (P=0·035) regression models. Conclusion Baseline lipoprotein(a) concentrations in patients admittedwith acute coronary syndromes are associated with an increasedrisk of cardiac death. For patients with myocardial infarctiona concentration of 30mg.dl^–1appears appropriate as a riskdiscriminator; for patients admitted with unstable angina, however,much lower concentrations of lipoprotein(a) appear to be prognosticallyimportant.     

Beneficial effect of enalapril on left ventricular remodelling in patients with a severe residual stenosis after acute anterior wall infarction

OBJECTIVE: The present study was designed to evaluate the effects of earlyangiotensin converting enzyme (ACE) inhibition on left ventricularenlargement in patients with anterior wall infarction followingreperfusion therapy. METHODS: Seventy-one consecutive patients with an anterior wall myocardialinfarction were randomly allocated to enalapril (n=36) or placebo(n=35). All patients received either thrombolytic therapy (n=46)or underwent primary coronary angioplasty (n=25). Medicationwas started within 48 h admission to hospital and continuedfor 48 weeks. The process of left ventricular remodelling wasassessed with two-dimensional echocardiography at 3 weeks and1 year after the acute onset, and was related to the severityof the residual stenosis of the infarct-related artery. RESULTS: Baseline left ventricular ejection fraction was 39·2±8·7%.During the study period, left ventricular end-diastolic volumeindex increased from 48·2±9·9 ml. m^–2to 54·6±12·2 ml. m^–2 at 3 weeks,and to 59·4±170 ml. m^–2 after 1 year incontrol patients (P<0·001). In the enalapril-treatedpatients, left ventricular end-diastolic volume index increasedfrom 50·0±16·1 to 57·7±19·3ml. m^–2 at 3 weeks, and to 61·9±22·7ml. m^–2 after 1 year (P<0·001). Both at 3 weeksand after 1 year, no overall differences in left ventricularvolumes were observed between the enalapril and the placebogroup (both ns). However, patients with a residual stenosisseverity of 70% in the infarct-related artery (n=43) showedsignificant attenuation of remodelling by enalapril (n=22) whencompared to placebo (n=21). In patients on enalapril, left ventricularend-diastolic volume index increased from 470±130 to53·7±17·7 ml. m^–2 compared to 48·0±9·6to 60·3±16·3 ml . m^–2 in controlpatients (P<0·03). Also diastolic filling parameterswere significantly improved in patients with 70% residual stenosis. CONCLUSION: In patients with an anterior wall infarction and a severe residualinfarct-related coronary artery stenosis following reperfusion,treatment with enalapril prevents the process of left ventricularremodelling. As left ventricular dilatation is an early processwe suggest that treatment with ACE inhibition should be startedas soon as possible in this group of patients.     

Good exercise capacity at hospital discharge predicts recovery of baroreflex sensitivity after myocardial infarction

Myocardial infarction results in depressed baroreflex sensitivity,which has been shown to be associated with increased risk ofventricular arrhythmias and sudden death. We measured baroreflexsensitivity in 37 patients with acute myocardial infarctionbefore hospital discharge and 3 months after the infarctionto find out whether the baroreflex sensitivity recovers duringthat period. In addition, baroreflex sensitivity was assessedin 15 healthy controls. Baroreflex sensitivity was assessedfrom the regression line relating the change in R-R intervalto the change in systolic blood pressure following an intravenousbolus injection of phenylephrine. There was a wide inter-individualvariation in the change of baroreflex sensitivity (Abaroreflexsensitivity) in infarction patients, but the average baroreflexsensitivity showed no significant change during the 3-monthfollow-up (10.2 +5.6 to 11.8 ± 7.5 ms. mmHg ^–1,ns) and remained lower than the baroreflex sensitivity of thecontrols (16.4 ± 9.7 ms. mmHg^–1, P<0.05). Baroreflexsensitivity correlated significantly with exercise capacitymeasured before hospital discharge. When the patients were dividedinto tertiles according to the baroreflex sensitivity ( –3.3 ± 1.5 ms. mmHg^–1 in the lowest tertile, 1.0± 1.0 ms. mmHg^–1 in the middle tertile and 7.5± 40 ms. mmHg^–1 in the highest tertile) the exercisecapacity was found to increase from the lowest to the highesttertile (exercise time 357 ± 115 s, 418 ± 126s and 461 ± 141 s, respectively; P<0.05 lowest vshighest tertile). Patients with a low exercise tolerance (exercisetime <360 s) showed a significantly smaller Abaroreflex sensitivitythan patients with a good exercise tolerance (exercise time480s) ( – 0.5±4.4 vs 5.3 ± 5.4ms. mmHg^–1,P<0.05), respectively. Baroreflex sensitivity was not relatedto the location or type of infarction, thrombolytic therapy,presence of angina pectoris or left ventricular function atthe time of discharge. In conclusion, exercise capacity assessedbefore hospital discharge seems to be a predictor of baroreflexsensitivity recovery in patients with a recent myocardial infarction.     

Critical assessment of two-dimensional echocardiographic estimation of the mitral valve area in rheumatic mitral valve disease: calcific deposits in the valve as a major determinant of the accuracy of the method

The accuracy of two-dimensional echocardiographic estimationof the mitral valve area (MVA) and the effects which the morphologicalfeatures of the valve (degree of stenosis, coexistent regurgitation,extent of calcific deposits) exert on the approximation of sucha measurement have been evaluated. In 29 patients, who underwent surgical replacement of a rheumaticmitral valve, correlation was assessed between the echocardiographicvalues of MVA and the anatomical ones measured on excised valvesby means of a sizer set to detect area differences up to 0.1cm² Though the correlation obtained was statistically significant(P <0.001) the percentage deviation (%) between the two seriesof measurements was appreciable (29.38 ± 20.14%, mean± 1 s.d.). The degree of stenosis and the presence or absence of regurgitationdid not affect %. Only the amount of calcific deposits, evaluatedfrom the radiographs of the excised valves, influenced the discrepancybetween the two methods, % being significantly higher (P <0.05) in the calcified valves than in the not or minimally calcifiedones. Though the two-dimensional echocardiographic estimates ofM VAin rheumatic mitral valve disease are correlated with the anatomicalarea, their predictive value in the estimation of the true orificesize is poor in the individual patient, in view of the largediscrepancy between the echocardiographic and anatomical measurementsfound in our study.     

Angioscopic evaluation of prolonged vs standard balloon inflations during coronary angioplasty: A randomized study

To study the immediate effects of prolonged total balloon inflationduring PTCA, 41 patients (44 lesions) with chronic-stable anginawere randomized for prolonged sequential inflations (three tofive inflations of 3 to 5 min each, for a total duration of 12 min, group 1, n=20 lesions) or ‘standard’ sequentialinflations (three to five inflations of 1 min each, for a totalduration of 3 min, group 2, n-24 lesions). The mean durationof total balloon inflation time was 958 ± 129 s in group1 vs 205 ±46 s in group 2. Results of angioplasty wereassessed on both angiography and percutaneous transluminal coronaryangioscopy performed immediately after the procedure. High qualityimaging of the coronary lumen and lesion morphology was possibleon angioscopy in all patients without any complications. Post-PTCAangiographic percent diameter stenosis was significantly lessin group 1 compared to group 2: 26 ± 10% vs 36 ±8% (P<0.05). On angioscopy, flaps were seen in 16 patientsin group 2, but in only six in group 1 (P<0.02). There wasno difference in the incidence of thrombi on angioscopy betweenthe two groups (group 1: nine cases, group 2: 10 cases). Sensitivityof angiographic detection of flaps and thrombi was poor: 10%and 12% respectively. One patient in each group developed alongitudinal dissection, detected on both angiography and angioscopy. Conclusions: (1) prolonged sequential balloon inflations leadto less residual luminal stenosis after PTCA, with a decreasedincidence of intimal flaps in comparison with standard inflations.(2) Post-PTCA transluminal coronary angioscopy is safe and offersbetter assessment of luminal effects of PTCA than angiography.     

Significance of ST-segment elevation during dobutamine-stress echocardiography in patients with acute myocardial infarction treated with thrombolysis

BACKGROUND: Stress-induced ST-segment elevation in patients with recentmyocardial infarction treated with thrombolysis has not beenextensively investigated. According to the results of previousstudies it may represent residual myocardial ischaemia or dyskinesiain the infarcted region. The aim of the study was to analysethe significance of dobutamine-induced ST-segment elevationin the infarcted area in a consecutive group of patients (n=42,41 men, mean age 53 ± 7 years) with a first acute myocardialinfarction treated with thrombolysis within 6 h from symptomsonset. METHODS AND RESULTS: All patients underwent dobutaminestress echocardiography (upto 40 µg. kg^–1. min^–1+ atropine) 7 ±3 days from the acute event and coronary arteriography within1 month from the test. Significant ST-segment elevation wasdefined as a shift 1 mm during dobutamine compared to baselinein at least two contiguous infarct-related leads; a correlationwas made between the site of ST-segment elevation and wall motionchanges during dobutamine. Dobutamine-induced ST-segment elevationin 23/42(55%) patients (group 1) while no changes were observedin 19/23 (45%) patients (group 2). Compared to group 2, group1 patients showed a higher asynergy score index (1·72± 0·24 vs 1·50 ± 0·32, P<0·02)and a higher number of asynergic segments (5·04 ±1·9 vs 4·11 ± 1·8), at baseline,a higher incidence of baseline and/or stressinduced dyskinesia(39 vs 10%, P<0·05) in the infarct-related regionand a higher percentage of occluded infarct-related arteries(48 vs 0%, P<0·001). In the 42 patients studied, asignificant correlation was found between baseline ST-segmentelevation and baseline asynergy score index (RS=0·56,P<000l) and between ST-segment elevation and asynergy scoreindex at peak stress (RS=0·55, P<0·001). Theincidence of reversible wall motion abnormalities indicativeof myocardial viability and residual myocardial ischaemia wassimilar in the two groups (87 vs 84% and 74 vs 68%, respectively),while the number of segments with irreversible akinesia indicativeof myocardial necrosis was higher in group 1 compared to group2 (1·5 ± 14 vs 0·9 ± 1·4).Among the 23 patients of group 1 with dobutamine-induced ST-segmentelevation, six had no reversible wall motion abnormalities indicativeof myocardial ischaemia; of the 17 patients with myocardialischaemia, 11 had 50% and six had 50% of basally asynergic segmentsshowing reversible wall motion abnormalities. CONCLUSIONS: In patients with recent thrombolyzed myocardial infarction dobutamine-inducedST-segment elevation is associated with a larger akinetic areain basal conditions and either with reversible wall motion abnormalitiesindicative of myocardial ischaemia or with irreversible or minimallyreversible wall motion abnormalities in the infarct area duringthe test. Thus, dobutamine echocardiography provides usefulinformation for the interpretation of stress-induced ST-segmentelevation and clinical management of these patients.