Concordance between dobutamine Doppler tissue imaging echocardiography and rest reinjection thallium-201 tomography in dysfunctional hypoperfused myocardium

OBJECTIVE—To evaluate the efficiency of the new technique colour Doppler tissue imaging (DTI) by studying the concordance between dobutamine DTI, standard grey scale echocardiography (SE), and rest-reinjection TI-201 tomography (TI) in dysfunctional myocardium.
PATIENTS—23 patients with chronic wall motion abnormalities and proven coronary artery disease (> 70% diameter stenosis of at least one major coronary artery at angiogram).
METHODS—The contractile reserve and the resting perfusion characteristics of dysfunctional myocardial segments were assessed with low dose dobutamine SE and/or DTI (2.5 up to 20 γ/kg/min) and TI on a semiquantitative basis. The DTI or SE data were separately compared with TI, on the basis of a 13 segment ventricular model. The resulting score of combined DTI and SE was also compared with TI. Finally the results obtained from DTI were compared with SE.
RESULTS—A total of 142 severely hypokinetic or akinetic segments were visualised. The viability study was feasible in 127 (89%) and 121 (85%) segments with DTI and SE, respectively. TI detected viability more frequently than DTI (84 v 61, p < 0.001) and SE (80 v 50, p < 0.001). However, as many viable segments were detected with combined DTI and SE as with TI (78 v 84, NS). The κ values between TI and SE, DTI or combined SE and DTI were 0.38, 0.45, and 0.57, respectively, and increased to 0.52 and 0.76, respectively, for SE and DTI versus TI when mid-anterior and mid-inferior segments only were considered. The κ value between SE and DTI was 0.34.
CONCLUSIONS—DTI is a helpful adjunct to SE, when using low dose dobutamine. This combination revealed as many viable segments as TI and showed a better agreement than DTI or SE alone for the assessment of myocardial viable segments evidenced by TI.


Keywords: colour Doppler tissue imaging; hibernating myocardium; thallium 201 single photon emission computed tomography; stress echocardiography     

Assessment of internal mammary artery and saphenous vein graft patency and flow reserve using transthoracic Doppler echocardiography

OBJECTIVE—To investigate transthoracic Doppler echocardiography in the identification of coronary artery bypass graft (CABG) flow for assessing graft patency.
DESIGN—The initial study group comprised 45 consecutive patients with previous CABG undergoing elective cardiac catheterisation for recurrent ischaemia. The Doppler variables best correlated with angiographic graft patency were then tested prospectively in a further 84 patients (test group).
SETTING—Three tertiary referral centres.
INTERVENTIONS—Flow velocities in grafts were recorded at rest and during hyperaemia induced by dipyridamole (0.56 mg/kg/4 min), under the guidance of transthoracic colour Doppler flow mapping. Findings on transthoracic Doppler were compared with angiography.
MAIN OUTCOME MEASURES—Feasibility of identifying open grafts by Doppler and diagnostic accuracy for Doppler detection of significant ( 70%) graft stenosis.
RESULTS—In the test group the identification rate for mammary artery grafts was 100%, for saphenous vein grafts to left anterior descending coronary artery 91%, for vein grafts to right coronary artery 96%, and for vein grafts to circumflex artery 90%. Coronary flow reserve (the ratio between peak diastolic velocity under hyperaemia and at baseline) of < 1.9 (95% confidence interval 1.83 to 2.08) had 100% sensitivity, 98% specificity, 87.5% positive predictive value, and 100% negative predictive value for mammary artery graft stenosis. Coronary flow reserve of < 1.6 (95% CI 1.51 to 1.73) had 91% sensitivity, 87% specificity, 85.4% positive predictive value, and 92.3% negative predictive value for significant vein graft stenosis.
CONCLUSIONS—Transthoracic Doppler can provide non-invasive assessment of CABG patency.


Keywords: blood flow; coronary artery disease; coronary artery bypass graft; echocardiography     

Quantitative contrast echocardiographic assessment of collateral derived myocardial perfusion during elective coronary angioplasty

OBJECTIVE—To determine whether myocardial contrast echocardiography can be used to quantify collateral derived myocardial flow in humans.
METHODS—In 25 patients undergoing coronary angioplasty, a collateral flow index (CFI) was determined using intracoronary wedge pressure distal to the stenosis to be dilated, with simultaneous mean aortic pressure measurements. During balloon occlusion, echo contrast was injected into both main coronary arteries simultaneously. Echocardiography of the collateral receiving myocardial area was performed. The time course of myocardial contrast enhancement in images acquired at end diastole was quantified by measuring pixel intensities (256 grey units) within a region of interest. Perfusion variables, such as background subtracted peak pixel intensity and contrast transit rate, were obtained from a fitted γ variate curve.
RESULTS—16 patients had a left anterior descending coronary artery stenosis, four had a left circumflex coronary artery stenosis, and five had a right coronary artery stenosis. The mean (SD) CFI was 19 (12)% (range 0-47%). Mean contrast transit rate was 11 (8) seconds. In 17 patients, a significant collateral contrast effect was observed (defined as peak pixel intensity more than the mean + 2 SD of background). Peak pixel intensity was linearly related to CFI in patients with a significant contrast effect (p = 0.002, r = 0.69) as well as in all patients (p = 0.0003, r = 0.66).
CONCLUSIONS—Collateral derived perfusion of myocardial areas at risk can be demonstrated using intracoronary echo contrast injections. The peak echo contrast effect is directly related to the magnitude of collateral flow.


Keywords: collateral circulation; quantitative myocardial contrast echocardiography; intracoronary pressure; myocardial perfusion     

Dobutamine stress echocardiography versus quantitative technetium-99m sestamibi SPECT for detecting residual stenosis and multivessel disease after myocardial infarction

OBJECTIVE—To compare the relative accuracy of dobutamine stress echocardiography (DSE) and quantitative technetium-99m sestamibi single photon emission computed tomography (mibi SPECT) for detecting infarct related artery stenosis and multivessel disease early after acute myocardial infarction.
DESIGN—Prospective study.
SETTING—University hospital.
METHODS—75 patients underwent simultaneous DSE and mibi SPECT at (mean (SD)) 5 (2) days after a first acute myocardial infarct. Quantitative coronary angiography was performed in all patients after imaging studies.
RESULTS—Significant stenosis (> 50%) of the infarct related artery was detected in 69 patients. Residual ischaemia was identified by DSE in 55 patients and by quantitative mibi SPECT in 49. The sensitivity of DSE and mibi SPECT for detecting significant infarct related artery stenosis was 78% and 70%, respectively, with a specificity of 83% for both tests. The combination of DSE and mibi SPECT did not change the specificity (83%) but increased the sensitivity to 94%. Mibi SPECT was more sensitive than DSE for detecting mild stenosis (73% v 9%; p = 0.008). The sensitivity of DSE for detecting moderate or severe stenosis was greater than mibi SPECT (97% v 74%; p = 0.007). Wall motion abnormalities with DSE and transient perfusion defects with mibi SPECT outside the infarction zone were sensitive (80% v 67%; NS) and highly specific (95% v 93%; NS) for multivessel disease.
CONCLUSIONS—DSE and mibi SPECT have equivalent accuracy for detecting residual infarct related artery stenosis of  50% and multivessel disease early after acute myocardial infarction. DSE is more predictive of moderate or severe infarct related artery stenosis. Combined imaging only improves the detection of mild stenosis.


Keywords: myocardial infarction; dobutamine echocardiography; single photon emission computed tomography; SPECT; myocardial ischaemia     

Functional assessment of coronary artery stenosis by Doppler derived absolute and relative coronary blood flow velocity reserve in comparison with 99mTc MIBI SPECT

OBJECTIVE—To determine the relation between the relative and absolute coronary blood flow velocity reserve (CFVR) compared with the results of ^99mTc MIBI single photon emission computed tomography (SPECT).
METHODS—In 37 patients with one vessel disease, ^99mTc MIBI SPECT was performed before angioplasty, two to three weeks after angioplasty, and at six months' follow up. CFVR was measured distal to the stenosis (dCFVR) as well as in a reference coronary artery before angioplasty, immediately after angioplasty, and at late follow up. Relative CFVR (rCFVR) was calculated as the ratio between dCFVR and CFVR measured in the reference coronary artery. The optimal thresholds for reversible perfusion defects were calculated using receiver operating characteristic curves.
RESULTS—The agreement for the full range of coronary artery stenosis (n = 107, mean (SD) diameter stenosis 48 (28)%, range 0-98%) between dCFVR (cut off value 1.9) and rCFVR (cut off value 0.65) with ^99mTc MIBI SPECT was 81% and 85%, respectively. In intermediate lesions (n = 49, diameter stenosis range 30-75%) the agreement between dCFVR (cut off value 2.0) and ^99mTc MIBI SPECT was 72%, which increased to 78% using the rCFVR (cut off value 0.65).There was a strong linear relation between dCFVR and rCFVR (r = 0.93, p < 0.0001).
CONCLUSIONS—A best cut off value for dCFVR of 1.9 corresponds with a best cut off value of 0.65 for rCFVR, within the full range of coronary narrowings. Intracoronary blood flow velocity analysis could obviate the need for additional myocardial perfusion scintigraphy in the majority of patients.


Keywords: intracoronary Doppler; relative coronary blood flow velocity reserve; ^99mTc MIBI single photon emission computed tomography     

Comparison of myocardial contrast echocardiography with NC100100 and (99m)Tc sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

OBJECTIVE—To determine whether myocardial contrast echocardiography (MCE) following intravenous injection of perfluorocarbon microbubbles permits identification of resting myocardial perfusion abnormalities in patients who have had a previous myocardial infarction.
PATIENTS AND INTERVENTIONS—22 patients (mean (SD) age 66 (11) years) underwent MCE after intravenous injection of NC100100, a novel perfluorocarbon containing contrast agent, and resting ^99mTc sestamibi single photon emission computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect.
RESULTS—Among the 203 normally contracting segments, 151 (74%) were normally perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptake was mainly found among normally contracting segments from the inferior wall. By contrast, with MCE poor myocardial opacification was noted essentially among the normally contracting segments from the anterior and lateral walls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects by SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities were seen more frequently among akinetic than hypokinetic segments. MCE correctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exclusion of segments with attenuation artefacts (defined as abnormal myocardial opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of the detection of SPECT perfusion defects by MCE.
CONCLUSIONS—The data suggest that MCE allows identification of myocardial perfusion abnormalities in patients who have had a previous myocardial infarction, provided that regional wall motion is simultaneously taken into account.


Keywords: myocardial contrast echocardiography; NC100100; single photon emission computed tomography; perfusion     

Lesion characteristics of acute myocardial infarction: an investigation with intravascular ultrasound

OBJECTIVE—To use intravascular ultrasound (IVUS) to compare plaque morphology in acute myocardial infarction and stable angina pectoris.
DESIGN—Retrospective study.
SETTING—Primary care hospital.
PATIENTS—59 consecutive cases of acute myocardial infarction and 50 consecutive cases of stable angina pectoris.
METHODS—IVUS was used before coronary intervention.
MAIN OUTCOME MEASURES—Plaque morphology (incidence of eccentric plaque, subtle dissections, low echoic thrombus, calcification, echolucent areas, and bright speckled echo material), assessed visually using IVUS.
RESULTS—There were no significant differences in plaque eccentricity or calcification between the two groups, but low echoic thrombus (acute myocardial infarction 15% v stable angina pectoris 0%), subtle dissections (37% v 4%), echolucent areas (31% v 0%), and bright speckled echo material (90% v 0%) were more common in the infarction group than in the stable angina group (p < 0.001 for all). There was a longer time between the onset of symptoms and the IVUS examination in patients with low echoic thrombus than in those without (p < 0.03).
CONCLUSIONS—Low echoic thrombus, subtle dissections, echolucent areas, and bright speckled echo material are morphological characteristics associated with plaque at the time of acute myocardial infarction. These findings correspond pathologically to ruptured plaque.


Keywords: intravascular ultrasound; acute myocardial infarction; plaque morphology     

Relation between the kinetics of thallium-201 in myocardial scintigraphy and myocardial metabolism in patients with acute myocardial infarction

Objective—To investigate the relations between myocardial metabolism and the kinetics of thallium-201 in myocardial scintigraphy.
Methods—46 patients within six weeks after the onset of acute myocardial infarction underwent resting myocardial dual isotope, single acquisition, single photon emission computed tomography (SPECT) using radioiodinated 15-iodophenyl 3-methyl pentadecaenoic acid (BMIPP) and thallium-201, exercise thallium-201 SPECT, and positron emission tomography (PET) using nitrogen-13 ammonia (NH₃) and [F18]fluorodeoxyglucose (FDG) under fasting conditions. The left ventricle was divided into nine segments, and the severity of defects was assessed visually.
Results—In the resting SPECT, less BMIPP uptake than thallium-201 uptake was observed in all of 40 segments with reverse redistribution of thallium-201, and in 21 of 88 segments with a fixed defect of thallium-201 (p < 0.0001); and more FDG uptake than NH₃ uptake (NH₃-FDG mismatch) was observed in 35 of 40 segments with reverse redistribution and in 38 of 88 segments with fixed defect (p < 0.0001). Less BMIPP uptake in the resting SPECT was observed in 49 of 54 segments with slow stress redistribution in exercise SPECT, and in nine of 17 segments with rapid stress redistribution (p < 0.0005); NH₃-FDG mismatch was observed in 42 of 54 segments with slow stress redistribution and in five of 17 segments with rapid stress redistribution (p < 0.0005).
Conclusions—Thallium-201 myocardial scintigraphy provides information about not only myocardial perfusion and viability but also about myocardial metabolism in patients with acute myocardial infarction.

Keywords: thallium-201 SPECT;  BMIPP SPECT;  FDG PET;  myocardial infarction;  redistribution     

Dobutamine echocardiography predicts functional outcome after revascularisation in patients with dysfunctional myocardium irrespective of the perfusion pattern on resting thallium-201 imaging

OBJECTIVE—To evaluate whether the predictive value of dobutamine echocardiography for assessing contractile reserve was altered by differing patterns of regional myocardial perfusion.
PATIENTS—31 consecutive patients with symptomatic congestive heart failure (left ventricular ejection fraction < 35%) caused by coronary artery disease.
SETTING—A district general hospital.
METHODS—Thallium-201 perfusion imaging and low dose dobutamine (5-15 µg/kg/min) echocardiography were performed and resting echocardiography was repeated three months after revascularisation. Perfusion pattern and systolic wall thickening were compared using a 12 segment left ventricular model.
RESULTS—Of the 273 severely dysfunctional segments, 106 (39%) showed a normal perfusion and 167 (61%) an abnormal pattern. After revascularisation, recovery occurred in 71 of the segments with a normal perfusion pattern, and in these a dobutamine response was observed in 61 (86%); recovery also occurred in 56 segments with a mild to moderate abnormality of perfusion, and in these a dobutamine response was seen in 46 (81%) (NS). After revascularisation, the positive and negative predictive values for recovery of dysfunctional segments, where the majority were abnormally perfused, were 88% and 86%, respectively. Systolic wall thickening score indices improved from (mean (SD)) 3.21 (0.58) to 2.6 (0.66) (p < 0.001) after revascularisation in dobutamine responsive patients (n = 24) compared with patients who did not show a dobutamine response (2.86 (0.65) and 3.13 (0.56), p = 0.61, respectively).
CONCLUSIONS—Dobutamine echocardiography predicted improvement of dysfunctional myocardium after revascularisation irrespective of the resting perfusion pattern seen.


Keywords: dobutamine echocardiography; perfusion; revascularisation     

Left ventricular long axis disturbances as predictors for thallium perfusion defects in patients with known peripheral vascular disease

Objective—To compare resting long axis echocardiography with adenosine thallium-201 emission tomography in detecting myocardial ischaemic abnormalities in patients before peripheral vascular surgery.
Design—A prospective and blinded preoperative examination of resting left ventricular minor and long axes and myocardial perfusion during adenosine vasodilatation using thallium-201 emission tomography.
Setting—A tertiary referral centre for cardiac and vascular disease equipped with invasive, non-invasive, and surgical facilities.
Subjects—65 patients (40 men) with significant peripheral vascular disease, mean (SD) age 63 (10) years, and 21 control subjects of similar age.
Methods—Segments were classified as normal, with fixed or reversible defects according to thallium-201 myocardial perfusion tomography. Systolic long axis abnormalities were either reduced excursion and/or abnormal shortening after A2, and diastolic abnormalities either delayed onset of lengthening > 80 ms and/or reduced peak lengthening rate < 4.5 cm/s. Segmental perfusion defects were compared with the equivalent long axes; anteroseptal for septal, inferoseptal for posterior, and lateral for left side giving a total of 195 segments.
Results—Systolic long axis abnormalities predicted fixed thallium defects (sensitivity 86%, specificity 87%, positive predictive value 0.78, negative predictive value 0.93, p < 0.001), and diastolic abnormalities correlated with reversible perfusion defects (sensitivity 90%, specificity 85%, positive predictive value 0.72, negative predictive value 0.95, p < 0.001). Echocardiography characteristics of the true and false positive segments were not different in the site or the extent of abnormalities.
Conclusion—Systolic long axis abnormalities predict fixed and diastolic reversible thallium perfusion defects in patients with peripheral vascular disease. Ventricular long axis may thus have a value as a screening test before peripheral vascular surgery as well as providing a means of monitoring myocardial perfusion. The high negative predictive values indicate that a negative long axis study makes significant perfusion abnormalities very unlikely in patients with high pretest probability of coronary artery disease.

     

Impact of hypertension on the accuracy of exercise stress myocardial perfusion imaging for the diagnosis of coronary artery disease

AIM—To compare the accuracy of exercise stress myocardial perfusion single photon emission computed tomography (SPECT) imaging for the diagnosis of coronary artery disease in patients with and without hypertension.
METHODS—A symptom limited bicycle exercise stress test in conjunction with 99m technetium sestamibi or tetrofosmin SPECT imaging was performed in 332 patients (mean (SD) age, 57 (10) years; 257 men, 75 women) without previous myocardial infarction who underwent coronary angiography. Of these, 137 (41%) had hypertension. Rest SPECT images were acquired 24 hours after the stress test. An abnormal scan was defined as one with reversible or fixed perfusion defects.
RESULTS—In hypertensive patients, myocardial perfusion abnormalities were detected in 79 of 102 patients with significant coronary artery disease and in nine of 35 patients without. In normotensive patients, myocardial perfusion abnormalities were detected in 104 of 138 patients with significant coronary artery disease and in 16 of 57 patients without. There were no differences between normotensive and hypertensive patients in sensitivity (77% (95% confidence interval (CI) 69% to 86%) v 75% (95% CI 68% to 83%)), specificity (74% (95% CI 60% to 89%) v 72% (95% CI 60% to 84%)), and accuracy (77% (95% CI 70% to 84%) v 74% (95% CI 68% to 80%)) of exercise SPECT for diagnosing coronary artery disease. The accuracy of SPECT was greater than electrocardiography, both in hypertensive patients (p = 0.005) and in normotensive patients (p = 0.0001). For the detection of coronary artery disease in individual vessels, sensitivity was 58% (95% CI 51% to 65%) v 57% (95% CI 51% to 64%), specificity was 86% (95% CI 82% to 90%) v 85% (95% CI 81% to 89%), and accuracy was 74% (95% CI 70% to 78%) v 74% (95% CI 70% to 78%) in patients with and without hypertension (NS).
CONCLUSIONS—In the usual clinical setting, the value of exercise myocardial perfusion scintigraphy for diagnosing coronary artery disease is not degraded by the presence of hypertension.


Keywords: hypertension; coronary artery disease; exercise stress test; myocardial perfusion     

The grade of worsening of regional function during dobutamine stress echocardiography predicts the extent of myocardial perfusion abnormalities

AIM—To evaluate the angiographic, myocardial perfusion, and wall motion abnormalities in patients with severe compared with mild worsening of regional function during dobutamine stress echocardiography (DSE) for evaluation of myocardial ischaemia.
METHODS—147 patients with significant coronary artery disease and new or worsening wall motion abnormalities during DSE were enrolled. Left ventricular function was evaluated using a 16 segment/4 grade score model where 1 = normal and 4 = dyskinesis. Simultaneous sestamibi SPECT myocardial perfusion imaging was performed in all patients.
RESULTS—Severe worsening of regional function (an increase in wall motion score of two grades or more in  1 segment) was detected in 37 patients, while 110 patients had mild worsening (an increase in wall motion score of no more than one grade in  1 segment). Patients with severe worsening of regional function had more stenotic coronary arteries (2.31 (0.8) v 1.97 (0.8) (mean (SD)) (p <0.05), a higher prevalence of left anterior descending coronary artery disease (95% v 73%) (p < 0.05), a higher resting wall motion score index (1.71 (0.42) v 1.51 (0.40) (p = 0.01), and more stress perfusion defects (3.8 (1.5) v 2.8 (1.5) (p < 0.001) compared with patients with mild worsening. Multivariate analysis identified the number of stress perfusion defects (p < 0.005, χ² = 8.8) and the number of ischaemic segments on echocardiography (p < 0.05, χ² = 4.3) as independent variables associated with severe worsening of regional function.
CONCLUSIONS—The grade of worsening of regional function during DSE predicts the underlying extent of myocardial perfusion abnormalities. The occurrence of severe worsening of regional function is associated with variables known to predict worse prognosis in patients with coronary artery disease.


Keywords: coronary artery disease; myocardial perfusion; ventricular function; echocardiography     

Myocardial perfusion defects and associated systemic ventricular dysfunction in congenitally corrected transposition of the great arteries

Background—Patients with systemic ventricles of right ventricular morphology are at high risk of contractile dysfunction, the cause of which has not been fully elucidated.
Objective—To assess whether ischaemia or infarction contributes to ventricular impairment in unoperated patients with uncomplicated congenitally corrected transposition of the great arteries (TGA) by studying myocardial perfusion and function.
Setting—Paediatric and adult congenital cardiac clinics of a tertiary referral centre.
Patients—Five patients with congenitally corrected TGA but without associated structural cardiac defects (aged 3.5 to 34 years).
Interventions—Maximal exercise stress testing using standard or modified Bruce protocols. Sestamibi (technetium-99m methoxy isobutyl isonitrile) scanning after isotope injection at maximal exercise and rest.
Main outcome measures—Maximum exercise capacity; right ventricular myocardial perfusion, regional wall motion, and thickening; right ventricular ejection fraction.
Results—The two youngest patients (3.5 and 11 years) had normal exercise capacity for age, while the others had reduced exercise performance. Sestamibi scanning showed reversible myocardial ischaemia in four patients and fixed defects indicating infarction in five. Irreversible defects were mostly associated with impaired wall motion and thickening. The ejection fraction was normal (65%) in the youngest patient but < 55% in the others (mean (SD) 47(11)%).
Conclusions—Patients with unoperated congenitally corrected TGA have a high prevalence of myocardial perfusion defects, with consequent abnormalities of regional wall motion and thickening, and impaired ventricular contractility. These data suggest that ischaemia and infarction are important in the pathogenesis of ventricular failure in this condition.

Keywords: congenitally corrected transposition of the great arteries;  ventricular dysfunction;  myocardial perfusion;  sestamibi scanning     

Aortic balloon dilatation for congenital aortic stenosis: report of 90 cases (1986-98)

OBJECTIVE—To review 12 years of experience of balloon aortic valvoplasty in childhood.
DESIGN—Early and mid-term clinical and instrumental evaluation of 104 consecutive balloon aortic valvoplasties performed from 1986 to 1998.
SETTING—A tertiary referral centre for congenital heart disease.
PATIENTS—90 patients with congenital aortic stenosis: 20 neonates (group 1), 16 infants (group 2), and 54 children (group 3).
INTERVENTIONS—Balloon aortic valvotomy.
MAIN OUTCOME MEASURES—Doppler and peak to peak aortic gradient before and after valvoplasty, degree of aortic regurgitation before and after valvoplasty, early and late mortality, need for repeat intervention or surgery.
RESULTS—Balloon aortic valvoplasty produced a gradient reduction of > 50% in 59 patients, 12 having a residual peak to peak gradient of > 50 mm Hg. Early mortality included three procedure related and six procedure unrelated deaths. There were no intraprocedural deaths. Grade III aortic regurgitation occurred in 20 patients. Five non-lethal complications occurred. At a mean follow up of 5.1 (group 1), 5.7 (group 2), and 7.6 years (group 3), survival was 75%, 88%, and 96%, respectively. Redilatation was performed in three patients in group 1, one in group 2, and 10 in group 3. Surgery was necessary for six in group 1, one in group 2, and eight in group 3. Freedom from events at last follow up was 50%, 75%, and 64%, respectively. There was a residual maximum Doppler gradient of < 30 mm Hg in 22 patients and > 60 mm Hg in 23; 50 patients have mild to moderate aortic regurgitation.
CONCLUSIONS—Balloon aortic valvoplasty is effective and repeatable and offers good palliation for congenital aortic stenosis in childhood.


Keywords: aortic valve disease; paediatric cardiology; percutaneous valvotomy; interventional catheterisation     

Predictors of event-free survival after percutaneous mitral commissurotomy

Objective—To assess the long term functional result after percutaneous mitral commissurotomy and identify the predictors of event-free survival following 10 years of experience.
Design—Analysis of clinical, echocardiographic, and haemodynamic variables at baseline and after the procedure by univariate and multivariate analyses (Cox model).
Setting—University hospital.
Patients—532 consecutive patients receiving percutaneous mitral commissurotomy in the same institution.
Results—The mean (SD) follow up was 3.8 (4.0) years. Survival at 3, 5, and 7.5 years was 94%, 91%, and 83%, respectively; event-free survival was 84%, 74%, and 52%. Mitral valve anatomy was identified as the strongest independent predictor of event-free survival. Age, cardiothoracic ratio, mean pulmonary artery pressure, and mean echocardiographic mitral gradient after commissurotomy were also found to be independent predictors of long term functional result. Event-free survival was 92%, 84%, and 70% at 3, 5, and 7.5 years in patients with favourable anatomy (echo score = 1), 86%, 73%, and 34% in patients with intermediate anatomy (echo score = 2), and 45%, 25%, and 16% in patients with unfavourable anatomy (echo score = 3). In patients aged 65 years, the event-free survival rate was 80%, 70%, and 45% at 3, 5, and 7.5 years v 52%, 38%, and 17% in patients aged > 65 years.
Conclusions—The anatomical form of the mitral valve and the patient's age were the most powerful predictors of event-free survival. Patients with intermediate or unfavourable anatomy and those aged > 65 years have low 5 and 7.5 year event-free survival rates. This must be taken into account when discussing the indications for percutaneous mitral commissurotomy; immediate mitral valve replacement is a reasonable alternative to balloon mitral commissurotomy in patients with higher risk of functional deterioration after the procedure.

Keywords: valvoplasty; mitral valve stenosis     

Assessment of myocardial perfusion and contractile function by inotropic stress Tc-99m sestamibi SPECT imaging and echocardiography for optimal detection of multivessel coronary artery disease

Objective—To assess whether inotropic stress myocardial perfusion imaging, echocardiography, or a combination of the two could enhance the detection of multivessel disease, over and above clinical and exercise electrocardiographic data.
Design—100 consecutive patients investigated by exercise electrocardiography and diagnostic coronary arteriography underwent simultaneous inotropic stress Tc-99m sestamibi SPECT (MIBI) imaging and echocardiography. MIBI imaging and echocardiographic data were analysed using a 12 segment left ventricular model, and each segment was ascribed to a particular coronary artery territory. The presence of perfusion defects with MIBI imaging or of wall thickening abnormality with echocardiography in at least two coronary artery territories at peak stress was taken as diagnostic of multivessel disease. Arteriographic evidence of  50% stenosis was considered significant.
Results—56 patients had multivessel disease. The sensitivity of the combination of MIBI imaging and echocardiography for detecting this was greater than either MIBI imaging or echocardiography alone (82%, 68%, and 68%, respectively; p = 0.005). Clinical and exercise electrocardiographic variables gave an R² value of 18.2% for predicting multivessel disease. The addition of either MIBI imaging (R² = 29.2%; p = 0.002) or echocardiography (R² = 28.8%; p < 0.001) enhanced the detection of multivessel disease, and the inclusion of both had further incremental value (R² = 34.8%; p = 0.003). Age (p = 0.03), MIBI imaging (p = 0.007), and echocardiography (p = 0.001) were independent predictors of multivessel disease.
Conclusions—The assessment of both myocardial perfusion and contractile function by simultaneous inotropic stress MIBI imaging and echocardiography optimises the non-invasive detection of multivessel disease.

Keywords: multivessel disease;  inotropic stress;  SPECT imaging;  echocardiography     

Beneficial haemodynamic effects of insulin in chronic heart failure

OBJECTIVE—To characterise the central and regional haemodynamic effects of insulin in patients with chronic heart failure.
DESIGN—Single blind, placebo controlled study.
SETTING—University teaching hospital.
PATIENTS—Ten patients with stable chronic heart failure.
INTERVENTIONS—Hyperinsulinaemic euglycaemic clamp and non-invasive haemodynamic measurements.
MAIN OUTCOME MEASURES—Change in resting heart rate, blood pressure, cardiac output, and regional splanchnic and skeletal muscle blood flow.
RESULTS—Insulin infusion led to a dose dependent increase in skeletal muscle blood flow of 0.36 (0.13) and 0.73 (0.14) ml/dl/min during low and high dose insulin infusions (p < 0.05 and p < 0.005 v placebo, respectively). Low and high dose insulin infusions led to a fall in heart rate of 4.6 (1.4) and 5.1 (1.3) beats/min (p < 0.05 and p < 0.005 v placebo, respectively) and a modest increase in cardiac output. There was no significant change in superior mesenteric artery blood flow.
CONCLUSION—In patients with chronic heart failure insulin is a selective skeletal muscle vasodilator that leads to increased muscle perfusion primarily through redistribution of regional blood flow rather than by increased cardiac output. These results provide a rational haemodynamic explanation for the apparent beneficial effects of insulin infusion in the setting of heart failure.


Keywords: blood flow; heart failure; insulin; muscle     

Effect of meal induced splanchnic arterial vasodilatation on renal arterial haemodynamics in normal subjects and patients with cirrhosis

Aims—To investigate the relation between changesin splanchnic arterial haemodynamics and renal arterial haemodynamicsin controls and patients with cirrhosis.
Methods—Superior mesenteric artery pulsatilityindex (SMA-PI) and renal artery pulsatility index (R-PI) were measuredusing Doppler ultrasonography in 24 controls and 36 patients withcirrhosis. These measurements were repeated 30 minutes after ingestionof a liquid meal or placebo. Sixteen controls and 24 patients received the meal, and eight controls and 12 patients received placebo.
Results—In the fasting condition, patients withcirrhosis had a lower SMA-PI (p<0.01) and a greater R-PI (p<0.01)compared with controls. Placebo ingestion had no effect on splanchnicand renal haemodynamics. In contrast, ingestion of the meal caused anotable reduction in SMA-PI (p<0.01, p<0.01) and an increase in R-PI(p<0.01, p<0.01) in controls and patients with cirrhosis. The mealinduced haemodynamic change in SMA-PI was inversely correlated withthat in R-PI in controls (t=−0.42, p<0.05) and inpatients with cirrhosis (t=−0.29, p<0.05).
Conclusions—Results support the hypothesis thatrenal arterial vasoconstriction seen in patients with cirrhosis is oneof the kidney's homoeostatic responses to underfilling of thesplanchnic arterial circulation.

Keywords:cirrhosis; Doppler ultrasonography; pulsatilityindex; renal artery; superior mesenteric artery

     

Ventricular mass and diastolic function in patients infected by the human immunodeficiency virus

OBJECTIVE—Echocardiographic and Doppler analysis of myocardial mass and diastolic function in patients infected with HIV.
DESIGN—Case-control study.
SETTING—Tertiary referral centre, Huelva, Spain.
PATIENTS—61 asymptomatic patients with HIV infection and 32 healthy controls.
MAIN OUTCOME MEASURES—Time motion, cross sectional, and Doppler echocardiographic studies were performed, and left ventricular mass and diastolic function variables determined (peak velocity of early and late mitral outflow and isovolumic relaxation time).
RESULTS—Left ventricular mass index (LVMI) was decreased in patients compared with healthy controls (mean (SD): 76.7 (23.6) v 118.8 (23.5) g/m², p < 0.001). Linear regression analysis showed a correlation between LVMI and brachial fat and muscle areas. The ratio of peak velocities of early and late mitral outflow was decreased in HIV infected patients compared with controls (1.19 (0.44) v 1.58 (0.38), p < 0.001). This ratio was exclusively related to haemodynamic variables (heart rate, systolic and diastolic blood pressures). HIV infected patients had a prolonged isovolumic relaxation time (103.0 (10.5) v 72.9 (12.9) ms, p < 0.001). Isovolumic relaxation time was correlated only with brachial muscle area on multivariate analysis.
CONCLUSIONS—HIV infected patients had a reduced left ventricular mass index and diastolic functional abnormalities. These cardiac abnormalities are predominantly related to nutritional status.


Keywords: HIV infection; cardiac function; nutrition     

Operator independent left ventricular function monitoring during pharmacological stress echo with the new peak transcutaneous acceleration signal

BACKGROUND—As the myocardium contracts isometrically, it generates vibrations that can be measured with an accelerometer. The vibration peak, peak endocardial acceleration (PEA), is an index of contractility.
OBJECTIVE—To evaluate the feasibility of PEA measured by the cutaneous precordial application of the accelerometer sensor; and to assess the usefulness of PEA monitoring during pharmacological stress echocardiography.
DESIGN—Feasibility study.
SETTING—Stress echo laboratory.
PATIENTS—34 consecutive patients underwent pharmacological stress (26 with dipyridamole; 8 with dobutamine) and PEA monitoring simultaneously.
INTERVENTIONS—A microaccelerometer was positioned in the precordial region and PEA was recorded. Dipyridamole was infused up to 0.84 mg/kg in 10 minutes, and dobutamine up to 40 µg/kg/min in 15 minutes.
RESULTS—A consistent PEA signal was obtained in all patients. Overall mean (SD) baseline PEA was 0.26 (0.15) g (g = 9.8 m/s²), increasing to 0.5 (0.36) g at peak stress (+0.24 g, 95% confidence interval (CI) 0.14 to 0.34 g; p < 0.01). PEA increased from 0.26 (0.16) to 0.37 (0.25) g in the dipyridamole group (+0.11 g, 95% CI 0.08 to 0.16 g; p < 0.01), and from 0.29 (0.1) to 0.93 (0.37) g in the dobutamine group (+0.64 g, 95% CI 0.37 to 0.91 g; p < 0.01).
CONCLUSIONS—Using precordial leads this method offers potential for diagnostic application in the short term monitoring of myocardial function. PEA monitoring is feasible during pharmacological stress and documents left ventricular inotropic response quantitatively in a non-invasive and operator independent fashion.


Keywords: ventricular function; contractility; peak endocardial acceleration; stress echo