Restenosis after coronary angioplasty for rapidly progressive coronary stenosis

OBJECTIVES: We hypothesized that percutaneous transluminal coronary angioplastyperformed on coronary stenoses that have demonstrated rapidangiographic progression would be associated with a high riskof restenosis. BACKGROUND: High rates of restenosis have been documented after percutaneoustransluminal coronary angioplasty of unstable lesions and oflesions that recurrapidly after a successful initial angioplasty.This suggests that the ‘activity’ of the plaqueat the time of angioplasty may be an important factor determiningthe risk of restenosis. METHODS: In our institution we recommend angiographic follow-up for allpatients with successful percutaneous transluminal coronaryangioplasty. In this way we identified 86 consecutive patientswho, at the time of angiographic follow-up had not developedrestenosis at the dilated site, butrequired a further percutaneoustransluminal coronary angioplasty at a different site (whichwas successful). Based on quantitative angiographic measurements,45 of these lesions (rapidly progressive lesions) had significantlyincreased in severity in the interval between the two angiograms(7.7 ± 3.3 months) while 41 (stable lesions) had not.Rapid progression was defined as a >0.4 mm decrease in minimallumen diameter between initial angiography and percutaneoustransluminal coronary angioplasty. All 86 patients had furtherangiographic follow-up 6 months later. RESULTS: Baseline clinical and angiographic variables were similar inboth groups except that a higher proportion of patients in therapid progression group had unstable angina (20% vs 5% P<0.05).Late loss during follow-up did not differ statistically betweengroups (0.31 mm) and minimal lumen diameter at follow-up wasalso similar (stable lesion group=1.40 ± 0.48 mm; rapidlyprogressive lesion group=1.30 ± 0.59 mm). The loss index(late loss divided by acute gain) was also similar in both groups(0.45 ± 0.52 in the stable lesion group, 0.37 ±0.76 in the rapidly progressive lesion group). A strong correlationbetween acute gain and late loss was observed in the stablelesion group (r=0.61; P<0.0001); by contrast, there was norelationship between these two variables in the rapidly progressivelesion group (r=0.20; P=0.19). CONCLUSIONS: Percutaneous transluminal coronary angioplasty in patients withunstable angina or with early recurrence after a first percutaneoustransluminal coronary angioplasty is associated with anincreasedrisk of restenosis. By contrast, this study shows that angiographicinstability, as evidenced by rapid stenosis progression, hasno deleterious effect on the occurrence of restenosis. Percutaneoustransluminal coronary angioplasty thus appears as a reasonabletherapeutic option for coronary stenoses that have demonstratedrapid angiographic progression in the months prior to the procedure.     

Progression of coronary artery disease in young male post-infarction patients is linked to disturbances of carbohydrate and lipoprotein metabolism and to impaired fibrinolytic function

Aims To assess determinants of coronary artery disease progressionin men with previous myocardial infarction. Methods and Results A total of 102 unselected non-diabetic Swedish men (age 40·4±3·6,range 23–44 years) entered the study 3–6 monthsafter a first myocardial infarction. The programme includedmetabolic and haemostatic investigations and routine coronaryangiography at baseline, followed by re-angiography 5 yearslater. Of the original cohort, 76 patients underwent a secondangiogram. Separate semiquantitative scoring systems were usedfor diffuse coronary atherosclerosis and distinct stenoses in15 proximal coronary segments. Smoking, global severity of coronaryatherosclerosis and presence of multi-vessel disease at baseline(P<0·001) characterized patients with severe progressionof both diffuse and focal lesions. Higher plasma levels of lowdensity lipoprotein cholesterol (P<0·01) and low densitylipoprotein triglycerides (P<0·05), a lower plasmahigh density lipoprotein₂cholesterol level (P<0·05)and higher plasma plasminogen activator inhibitor-1 activity(P<0·05), together with a high baseline stenosis score(P<0·001) characterized patients with severe progressionof coronary atherosclerosis. On the other hand, more pronouncedfasting and post-prandial glycaemia (P<0·05), togetherwith higher plasma plasminogen activator inhibitor-1 activity(P<0·01) characterized severe progressors with respectto coronary stenosis. Multi-variate analysis identified thepresence of multi-vessel disease as an independent predictorof progression of both coronary atherosclerosis (P=0·008)and stenoses (P=0·007), whereas a high low density lipoproteintri-glyceride level (P<0·01) was independently relatedto progression of coronary atherosclerosis and a high fastingglucose level (P=0·02) to progression of coronary stenoses. Conclusion Disturbances in carbohydrate and lipoprotein metabolism andimpaired fibrinolytic function are associated with progressionof coronary artery disease in young male post-infarction patients.     

Anatomical progression of coronary artery disease in humans as seen by prospective, repeated, quantitated coronary angiography. Relation to clinical events and risk factors. The INTACT Study Group.

BACKGROUND. At present, there is extensive knowledge on the clinical course of coronary artery disease (CAD), whereas data on the underlying anatomical changes and their relation to clinical events are still limited. METHODS AND RESULTS. We investigated progression and regression of CAD prospectively over 3 years in 230 patients (average age, 53.2 years) with mild to moderate disease by applying quantitated, repeated coronary angiography. Minimal stenotic diameters, segment diameters, and percent stenosis were analyzed by the computer-assisted Coronary Angiography Analysis System (CAAS). Progression was defined either as an increase in percent stenosis of preexisting stenoses by greater than or equal to 20% including occlusions or as formation of new stenoses greater than or equal to 20% and new occlusions in previously angiographically "normal" segments. At first angiography, we found 838 stenoses greater than or equal to 20% (average degree, 39.3%) and 135 occlusions in the four major coronary branches (4.23 lesions per patient). At second angiography, 82 (9.8%) of the preexisting stenoses had progressed, 15 of them up to occlusion (1.8%; preocclusion degree averaging 46.6%; 29.7-65.6%). In addition, there were 144 newly formed stenoses (average degree, 39.2%) and 10 new occlusions. Hence, 25 (2.6%) of all stenoses had become occluded. Altogether, 129 patients (56.1%) showed progression: 68 (29.6%) with new lesions only, 27 (11.7%) with preexisting lesions, and 34 (14.8%) with both types. Regression (decrease in degree of stenoses greater than or equal to 20%) was present in 29 stenoses (3.6%) and 28 patients (12%). The incidence of new myocardial infarctions was low, with three originating from occluding preexisting stenoses and one from new stenoses; hence, only four (16%) of the 25 new occlusions led to myocardial infarctions. Risk factor analysis showed that cigarette smoking correlated significantly with the formation of new lesions (p = 0.001), whereas total cholesterol correlated with the further progression of preexisting stenoses (p = 0.017) but not with the incidence of new lesions. CONCLUSIONS. In patients with mild to moderate CAD, the angiographic progression is slow (in this study 18.7% of patients and 7% of stenoses per year) but exceeds regression (4.1% of patients and 1.2% of stenoses per year). Progression is predominantly seen in the formation of new coronary stenoses and less in growth of preexisting ones. Most of the stenoses were of a low degree (less than 50%), clinically not manifest including those going into occlusion and leading to myocardial infarction. Progression was influenced by risk factors, especially cigarette smoking (formation of new lesions) and high cholesterol levels (progression of preexisting stenoses).     

Percutaneous transluminal coronary angioplasty of aorta ostial, non-aorta ostial, and branch ostial stenoses: acute and long-term outcome

The acute and long-term outcome of 198 patients who underwentcoronary angioplasty of ostial stenoses was evaluated. Proceduralsuccess was achieved in 85% of aorta ostial stenoses, 90% ofnon-aorta ostial stenoses, and 87% of branch ostial stenoses(P=0–84). A major complication occurred in 5.9%, 6.3%,and 6–9% of patients who underwent aorta ostial, non-aortaostial, and branch ostial stenosis angioplasty, respectively(P=0.97). A greater residual stenosis (P=0.005) resulted fromangioplasty of aorta ostial lesions despite a greater inflationfrequency (P<0.001), inflation pressure (P<0.001), andtotal inflation duration (P<0.001). The restenosis rate washigher for aorta ostial lesions (71%) when compared to non-aortaostial (60%) and branch ostial lesions (32%) (P=0.01). However,since the denominator included only the 49% who returned forrepeat coronary angiography, the exact angiographic restenosisrate cannot be determined. The cumulative probability of survivalwas 99% at 1 year and 93% at 3 years. The 1 and 3 year freedomfrom death, myocardial infarction, bypass surgery, and repeatangioplasty was 70% and 57%, respectively. At census, 57% wereasymptomatic, and only 9% suffered severe angina. Coronary angioplastyof ostial stenoses can be carried out with an acceptable successand complication rate, and provides good symptomatic reliefand favourable long-term outcome. Randomized trials to comparenew angioplasty technology with balloon angioplasty will benecessary to select the best device therapy for ostial lesions.     

Quantitative coronary angiography in predicting functional significance of stenoses in an unselected patient cohort

Objectives. This study investigated the value of quantitative coronary angiography for predicting coronary flow reserve, as calculated from the transstenotic pressure gradient in a large, unselected patient cohort.Background. In patients with extensive coronary artery disease, quantitative coronary angiographic findings fail to correlate with functional variables of coronary stenoses. New developments in pressure-monitoring wire technology permitted validation in humans of the concept of myocardial fractional flow reserve as assessed from coronary pressure measurements.Methods. One hundred ten patients with normal left ventricular function were studied in the setting of coronary angioplasty. Quantitative coronary angiography was performed on-line using the ACA system. Myocardial and coronary fractional flow reserve were calculated from aortic and distal coronary pressures during maximal coronary hyperemia.Results. When data before and after angioplasty were pooled, a curvilinear relation was found between myocardial fractional flow reserve and both diameter stenosis (r = 0.79) and minimal lumen diameter (r = 0.82), and a linear relation was found between myocardial fractional flow reserve and angiographic stenosis flow reserve (r = 0.78). Correlations between quantitative angiographic and pressure-derived indexes, although significant, were characterized by a large dispersion of the values of myocardial fractional flow reserve for a similar angiographic degree of stenosis. Nevertheless, the sensitivity and specificity of a minimal lumen diameter <1.5 mm to predict myocardial fractional flow reserve <0.72 were 96% and 89%, respectively. The corresponding values for a diameter stenosis >50% were 93% and 85%, respectively.Conclusions. 1) In an unselected patient cohort, geometric indexes of stenosis severity derived from quantitative coronary angiography correlate significantly with physiologic variables, although these relations are imprecise in individual patients. 2) Nevertheless, the diagnostic accuracy of quantitative coronary angiography in predicting myocardial fractional flow reserve <0.72 is high and allows its use for clinical decision making in the individual patient during diagnostic or interventional procedures.     

Assessment of coronary artery stenosis during PTCA by measurement of the trans-stenotic pressure gradient: Comparison with quantitative coronary angiography

A fibreoptic pressure sensor mounted on an 0 018 inch guidewire(Pressure Guide®, RadiMedical Systems, Uppsala, Sweden)was used to measure the trans-stenotic pressure gradient in20 patients admitted for percutaneous transluminal coronaryangioplasty (PTCA) of a single, discrete stenosis. Pressuremeasurements were made both at rest and during maximal vasodilatationinduced by intracoronary injection of papaverine. From the ratioof distal coronary pressure divided by the proximal pressure,the relative coronary flow reserve was calculated. The aim ofthe study was to compare the different pressure-derived parametersby correlating them to stenosis geometry estimated by quantitativecoronary angiography. There was a moderate correlation betweenbaseline pressure gradient and percent area stenosi r= 0.64,P<0.001 and minimal cross-sectional area; r= 0.45, P<0005.A higher correlation was found between hyperaemic pressure gradientand area stenosis (r= 080, P<0001) and minimal cross-sectionalareas, respectively (r= 0.55, P<0 005). The best correlationwas found between relative coronary flow reserve and area stenosis(r= 0.86, P<0.001) and minimal cross-sectional area (r= 0.70,P<0001). In conclusion, pressure measurement using a pressure guidewireis useful as a complement to angiography in evaluation of coronarystenoses during PTCA. Pressures should be measured during maximalvasodilatation. Relative coronary flow reserve calculated fromthe pressure measurements provides additional information aboutthe fraction of normal maximal flow possible in the presenceof a stenosis.     

Angiography-derived functional assessment of left main coronary stenoses

Objectives

We aimed to evaluate the diagnostic accuracy of quantitative flow ratio (QFR) in left main (LM) coronary stenoses, using Fractional Flow Reserve (FFR) as reference.

Background

QFR has demonstrated a high accuracy in determining the functional relevance of coronary stenoses in non-LM. However, there is an important paucity of data regarding its diagnostic value in the specific anatomical subset of LM disease.

Methods

This is a retrospective, observational, multicenter, international, and blinded study including patients with LM stenoses. Cases with significant ostial LM disease were excluded. QFR was calculated from conventional angiograms at blinded fashion with respect to FFR.

Results

Sixty-seven patients with LM stenoses were analyzed. Overall, LM had intermediate severity, both from angiographic (diameter stenosis [%DS] 43.8 ± 11.1%) and functional perspective (FFR 0.756 ± 0.105). Mean QFR was 0.733 ± 0.159. Correlation between QFR and FFR was moderate (r = 0.590). Positive and negative predictive value, sensitivity and specificity were 85.4%, 64%, 85.4%, and 69.6% respectively. Classification agreement of QFR and FFR in terms of functional stenosis severity was 78.1%. Area under the receiver operating characteristics of QFR using FFR as reference was 0.82 [95% confidence interval [CI], 0.71−0.93], and significantly better than angiographic evaluation including %DS (area under the receiver-operating characteristic curve [AUC] 0.45 [95% CI, 0.32−0.58], p < 0.001) and minimum lumen diameter (AUC 0.60 [95% CI, 0.47−0.74], p < 0.001).

Conclusions

Compared with FFR, QFR has acceptable diagnostic performance in determining the functional relevance of LM stenosis, being better than conventional angiographic assessment. Nonetheless, caution should be taken when applying functional angiography techniques for the assessment of LM stenosis given its particular anatomical characteristics.     

Variability in estimation of coronary dimensions from 6F and 8F catheters

To investigate the suitability of diagnostic 6F catheters for coronary angiographic measures in the clinical setting, we determined the relative accuracy and reproducibility of the measures obtained with these catheters as scaling devices in 59 stenoses. Comparison was made with duplicate injections, obtained before angioplasty, using an 8F guiding catheter as scaling device. Intra- and interobserver variability was evaluated in 15 stenoses. The coefficient of variation averaged 18.3% for the minimal lumen diameter, 10.4% for the percent stenosis, and only 7.4% for the reference diameter. Reproducibility of angiographic measures done with the 6F catheter was similar to that obtained with the 8F catheter, although accuracy was lower with the 6F for the measurement of reference diameter. Thus, quantitative coronary angiography (QCA) measures derived from routine diagnostic angiograms may be suitable for determination of reference diameter, allowing enough precision for determination of the size of a coronary device for intervention, but these measures may lack accuracy for precise determination of minimum diameter and percent stenosis, making their use questionable in studies looking at individual changes in coronary stenosis dimensions. © 1996 Wiley-Liss, Inc.     

Angiographic progression in patients with angina pectoris and normal or near normal coronary angiograms who are restudied due to unstable symptoms

Background Syndrome X patients commonly remain symptomatic during follow-upand may be readmitted with unstable anginal symptoms. Angiographicdisease progression must be considered as a possible mechanismfor instability, particularly where multiple coronary risk factorsare present and an interval of several years has elapsed sinceprevious angiography. Methods and Results We reviewed data from 139 consecutive patients with chest painand normal or near normal coronary angiograms (101 patientswith completely normal angiograms and 38 patients with minimallumenal irregularities). During a 5-year period, 24 patients(19 women, median age 56 years) underwent repeat angiographydue to primary unstable angina (median interval between angiograms58 months (range 8–130 months)). This group included threepatients with minimal lumenal irregularities and four patientswith left bundle branch block. Only two patients had progressionto significant angiographic stenosis (>30% diameter reduction);both were male patients with minimal irregularities at baselineangiography, left bundle branch block and multiple coronaryrisk factors. However, overall only two of 18 (11%) patientswith one or more conventional coronary risk factors had angiographicprogression. Conclusion Unstable symptoms in patients with chest pain and previouslynormal or near normal coronary arteriograms are rarely due toangiographic disease progression. However, the presence of minimallumenal irregularities at baseline angiography and LBBB mayidentify a sub-group at increased risk.     

Assessment of severity of coronary narrowings by quantitative exercise echocardiography and comparison with quantitative arteriography

To determine the correlation of quantitative assessment of coronary narrowings with left ventricular functional impairment induced by exercise, 57 patients with 1-vessel coronary artery disease and without evidence of collateral flow were studied. A significant relation was observed between minimal cross-sectional area, percent area stenosis, minimal lumen diameter, percent diameter stenosis and the percentage of segmental area change from rest to peak exercise in a vascular distribution territory (r = 0.76, p less than 0.001; r = -0.55, p less than 0.001; r = 0.56, p less than 0.001; r = -0.75, p less than 0.001, respectively). For minimal cross-sectional area, the best cut-off value to separate significantly patients who had a decrease in contractility at peak exercise testing from those who had a normal response was 2 mm2 (p less than 0.001); for percent cross-sectional area stenosis, it was 75% (p less than 0.001); for minimal lumen diameter, it was 0.7 mm (p less than 0.001); and, for percent diameter stenosis, it was 85% (p less than 0.001). High cut-off values for angiographic variables are necessary to separate significantly patients who have a decrease in contractility at peak exercise testing from those who have a normal response. Several patients with mild coronary stenoses may have either normal or abnormal wall motion during exercise. Thus, exercise echocardiography is a useful tool in detecting the presence of fairly severe anatomic narrowing, whereas it is of limited clinical use in the assessment of intermediate coronary atherosclerotic lesions.     

Relative coronary flow velocity reserve improves correlation with stress myocardial perfusion imaging in assessment of coronary artery stenoses

STUDY OBJECTIVE: To evaluate the angiographic and coronary flow velocity parameters that best correlate with the results of stress myocardial perfusion imaging. DESIGN: Criterion standard. SETTING: Tertiary care center. PATIENTS: Forty-eight patients undergoing diagnostic coronary angiography for angina or silent ischemia. INTERVENTIONS: We performed angiographic and coronary flow velocity measurements at rest and during hyperemia at the post-stenotic segment and in the adjacent angiographically normal branch of the left coronary artery. Relative coronary flow velocity reserve (RCFVR) was calculated as the ratio of post-stenotic to reference vessel coronary flow velocity reserve (CFVR). The best cutoff points for reversible perfusion defects were calculated using receiver operating characteristic curves. MEASUREMENTS AND RESULTS: Post-stenotic CFVR showed fairly good correlations with minimal lumen diameter and percentage of diameter stenosis (r = 0.57 and r = 0.55, respectively; p < 0.001). RCFVR showed stronger correlations with these angiographic indexes of stenosis severity (r = 0.66 and r = 0.68, respectively; p < 0.0001). Based on receiver operating characteristic cutoff values (1.67 for post-stenotic CFVR and 0.64 for RCFVR), RCFVR had better agreement with myocardial perfusion imaging results, compared to post-stenotic CFVR (92% vs 75%, respectively). This agreement was more meaningful in patients with moderate coronary artery stenoses (50 to 75%). The area under the curve was 0.65 (not significant) for post-stenotic CFVR and 0.88 (p < 0.01) for RCFVR. CONCLUSIONS: RCFVR describes better than post-stenotic CFVR the functional significance of coronary artery stenoses.     

Restenosis and its determinants in first and repeat coronary angioplasty

Restenosis is the main problem limiting long-term success ofpercutaneous transluminal coronary angioplasty (PTCA) and ismost accurately evaluated by follow-up angiography. We comparedthe primary and long-term results of angioplasty in 268 consecutivepatients (293 segments) with first PTCA (PTCA 1, angiographicfollow-up 98%) and in 66 patients (76 segments) with repeatPTCA after restenosis (PTCA 2, angiographic follow-up 92%).Forty clinical, angiographic and procedural factors were assessedin relation to outcome. Primary success rate was higher in PTCA2 (91% vs 67.5%) and major complications were fewer (4.5% vs16%).Higher inflation pressure (7.9 ± 2.3 vs 6.8 ±1.8 atm, P<0.005) and larger balloons (3.5 ± 0.5 vs3.2 ± 0.5mm, P< 0.005) were used for PTCA 2, resultingin lesser residual stenosis (33 ± 16± vs 40 ±18%, P <0.05). Restenosis rate (>70%) after PTCA 1 andafter PTC A 2 (27% vs 36%, P = NS) and the mean time to recurrence(4.7 vs 5.3 months, P = NS) were similar. Procedural factorswere the main determinants of long-term success in primary PTCA.The restenosis risk was independently related to residual stenosis>45% (P<0.001), variant angina (P<0.05) and multivesseldisease (P<0.05) after PTCA 1 and to male sex (P<0.001)and higher inflation pressure (P<0.05) after PTCA 2. Mildto moderate intimal tearing was associated with less restenosisafter PTC A 1, but not after PTCA 2. Including 9 patients (10segments) with a third PTCA, 70% of the 66 patients with repeatPTCA had a successful long-term outcome. Repeat angioplastyshould therefore be considered as an integral part of PTCA therapy.Restenosis however remains a major concern. An optimal primaryresult with a minimal residual stenosis is decisive for firstPTCA, whereas avoidance of a dissection by using lower inflationpressure on a restenosis might improve the long-term outcomeof repeat PTCA.     

Comparison between regional myocardial perfusion reserve and coronary flow reserve in the canine heart

Diameter stenosis and flow reserve are indices of morphologicaland functional severity of coronary artery stenosis. Flow reservecan be determined at coronary arterial or at myocardial level.In the presence of functional collateral circulation, coronaryflow reserve and myocardial perfusion reserve may differ. We studied coronary flow, coronary flow reserve and myocardialperfusion reserve in an open chest dog model with intact collateralcirculation, before and after induction of coronary artery stenosis.Coronary flow was determined with perivascular ultrasonic flowprobes and myocardial perfusion reserve from digital angiographicimages, in the stenotic as well as the adjacent non-stenoticcoronary arteries. Before induction of a stenosis, a significant correlation existedbetween coronary flow reserve and myocardial perfusion reserveof the left anterior descending (r=0·59; P<0·005)and the left circumflex arteries (r=0·84, P<0·005).In stenotic arteries, coronary flow reserve and myocardial perfusionreserve decreased significantly (P<0·005), but inthe adjacent non-stenotic arteries coronary flow reserve wasnot affected Myocardial perfusion reserve in the non-stenoticadjacent left anterior descending artery decreased significantly(P<0·05) and no correlation was found between coronaryflow reserve and myocardial perfusion reserve, whereas in theadjacent non-stenotic left circumflex artery there was no statisticallysignificant decrease (4·1 ± 1·6 3·5± 1·4) but there was a good correlation betweencoronary flow reserve and myocardial perfusion reserve (r=0·85;P<0·005). This study demonstrates that, in the presence of a stenosisand functioning collateral circulation, coronary flow reserveis not a reliable predictor of myocardial perfusion reserve;both parameters provide mutually complementary information.     

Comparative evaluation of coronary stenoses using fluid dynamic equations and standard quantitative coronary arteriography

Traditional quantitative coronary arteriographic measurements have largely ignored geometric variables, which may be important in determining the obstructive nature of coronary stenoses. To illustrate the relation between standard quantitative coronary arteriography and calculated transstenotic fluid dynamics, 25 patients with 1-vessel disease referred for coronary angioplasty were analyzed. Minimal lumen diameter and percent stenosis were measured and the values compared with calculations of pressure loss that used standard hydraulic formulas encompassing both frictional and separation components within the stenotic segments. Baseline flow velocity was assumed to equal 4 cm/s and normal hyperemic flow response was presumed to equal 5 times that of baseline. Fluid dynamic estimates suggested that initial translesional pressure gradients would develop at a minimal diameter of 0.6 mm (80% diameter), with an exponentially severe pressure differential beyond a minimal coronary diameter of 0.3 mm (92% diameter). Maximal velocities were calculated based upon an assumed normal hyperemic flow response of 5 times that of baseline, with the demonstration of early impairment of hyperemic flow reserve at minimal diameters of 1.2 mm (46% diameter). Furthermore, hyperemic flow reserve was completely abolished at a minimal diameter of 0.3 to 0.5 mm (89 to 92% diameter). Beyond a minimal diameter of 0.2 mm (93% diameter), resting hypoperfusion was anticipated with flow velocities below the initially assumed value (4 cm/s). Thus, it is feasible to estimate transstenotic pressure losses and maximal coronary flow velocity by applying Newtonian fluid dynamic equations to actual angiographic stenoses in man. These calculations generally correlate with traditional quantitative arteriographic estimates of stenosis severity, although other geometric parameters such as lesion length, "exit angle" and blood viscosity may alter transstenotic hemodynamics.     

Impact of compensatory enlargement of atherosclerotic coronary arteries on angiographic assessment of coronary artery disease

To determine whether compensatory enlargement of atherosclerotic coronary arteries occurs and to what degree it affects the angiographic assessment of coronary artery disease, we performed postmortem coronary angiography of 30 human hearts with suspected coronary artery disease and studied 70 histologic cross sections of the proximal left anterior descending artery and proximal right coronary artery. Angiographic and morphometric analyses of 50 stenoses in proximal and middle sections of the left anterior descending artery, right coronary artery, and left circumflex artery were performed. The control group of 10 human hearts without suspected coronary artery disease was evaluated in the same way. For this purpose, coronary arteries were filled with a methylmethacrylic radiopaque resin at a pressure of 100 mm Hg and closely embedded in a methylmethacrylic resin by use of which shrinkage and mechanical artifacts could be avoided. The area circumscribed by the internal elastic lamina was taken as a measure of the area of the arterial lumen if no plaque had been present. The angiographic and corresponding morphometric degree of stenosis was assessed. A significant correlation (r = 0.85, p less than or equal to 0.0001) was found between the internal elastic lamina area and the area of the plaque (lesion area), suggesting that coronary arteries may enlarge as lesion area increases. With the morphometric degree of stenosis, the expected anatomic diminution of the coronary artery was abolished (r = 0.79, p less than or equal to 0.0001), indicating compensatory enlargement in atherosclerotic segments. Accordingly, the degree of stenosis assessed from in vitro angiograms was underestimated. Compensatory coronary enlargement of the stenotic segment was the main reason for angiographic underestimation. The underestimation factor of up to 3.50 for very mild stenoses decreased to 1.37 at an angiographic degree of 50% area stenosis and 30% diameter stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of the results of percutaneous transluminal coronary angioplasty using an integrated ultrasound imaging-angioplasty Catheter

To evaluate the results percutaneous transluminal coronary angioplasty (PTCA), intra-vascular ultrasound imaging was performed in 32 proximal coronary arterial segments and in 16 atherosclerotic lesions after PTCA in 13 patients using a 5 Fr balloon catheter with an ultrasound transducer mounted just proximal to the balloon. Simultaneous angiographic measurements of vessel diameter were also performed using electronic calipers from contrast cine angiograms. There was good correlation between ultrasound and angiographic minimum luminal diameters of the normal proximal vessel (y = 0.59x + 1.49, r = 0.70, P<0.01, n = 32). However, the luminal diameter measured by intravascular ultrasound was significantly greater than when measured by contrast angiography (2.81±0.10 vs. 2.34±0.12mm, n = 16, P<0.001, mean ±SEM). Post-PTCA, there was good correlation between ultrasound and angiographic minimum luminal diameters of the lesion (y = 0.62x + 1.42, r=0.76, P<0.001, n = 16), but again luminal diameters were significantly greater when measured by intravascular ultrasound compared to contrast angiography (2.61±0.08 vs. 1.89 ± 0.10mm, n = 16, P<0.001). Furthermore, residual stenosis was significantly less when determined by intravascular ultrasound than by contrast angiography (7.3±2.0 vs. 18.1 ± 2.1%, n = 16, P<0.001). Intravascular ultrasound was able to detect coronary calcification that was not evident by contrast coronary angiography in 8 of 16 lesions. Post-PTCA, dissection was evident in four lesions by ultrasound, whereas dissection was appreciated in only three lesions by contrast angiography. We conclude that intravascular ultrasound can accurately measure the luminal diameter of coronary arteries both before and after PTCA and reveals more information about the lesion characteristics than does conventional contrast angiography.     

High frequency rotational ablation: an alternative in treating coronary artery stenoses and occlusions.

OBJECTIVE--To prove the safety and effectiveness of high frequency rotational ablation of coronary artery stenoses and occlusion in humans. SUBJECTS--106 patients with symptoms (91 men, 15 women) who had 67 significant stenoses, mainly types B and C, and 46-chronic occlusions. MAIN OUTCOME MEASURES--Mean change in diameter stenosis after rotational angioplasty alone and in combination with percutaneous transluminal coronary angioplasty immediately after treatment and 24 hours and six months later; restenosis rates at six months; complication of treatment. RESULTS--Rotational ablation could not be used in five stenoses and 16 chronic occlusions because of inability to reach or cross the lesion with the Rotablator guide wire. In four cases rotational ablation failed. Initial angiographic and clinical success by rotational ablation was achieved in 40 of the 67 stenoses (60%) and in 18 of the 46 chronic occlusions (39%). Additional balloon angioplasty was performed in 45 patients, increasing the success rates to 79% and 54%, respectively. In the 62 stenoses treated by rotational ablation the angiographic diameter stenoses were reduced from 76% (SD 14%) to 32% (14%) after Rotablator treatment alone and from 75% (11%) to 33% (17%) with additional balloon angioplasty. In the 30 chronic occlusions treated by rotational ablation the angiographic diameter stenoses were reduced to 38% (18%). At six months angiographic restenosis was evident in nine of the 25 (36%) stenoses treated with rotational ablation alone, in seven of the 22 (32%) stenoses treated with rotational and balloon angioplasty, and in 14 of the 24 (58%) chronic occlusions. There were no procedural deaths and two patients (2%) underwent emergency coronary artery bypass grafting. Although no transmural infarction occurred, there were five (6%) non-Q wave infarctions (two embolic side branch occlusions, two subacute occlusions, and one acute occlusion). Clinically insignificant slight increases in creatine kinase activity were seen in five patients (6%). Severe coronary artery spasm unresponsive to medical treatment was provoked in seven cases (8%). CONCLUSIONS--High frequency rotational ablation is a safe and effective method for treating type B and C coronary artery lesions with results comparable to percutaneous transluminal coronary balloon angioplasty. The combined use of rotational ablation and balloon angioplasty is feasible and is necessary in about half of all procedures, in most cases because the lumen created by the biggest burr is too small.     

Randomized trial of hormone therapy in women after coronary bypass surgery. Evidence of differential effect of hormone therapy on angiographic progression of disease in saphenous vein grafts and native coronary arteries

Clinical trials indicate that hormone therapy (HT) does not decrease cardiovascular disease events or angiographic coronary disease progression. The effects of HT on SVG vessels are unknown. To determine whether postmenopausal hormone therapy started after coronary bypass surgery (CABG) decreases saphenous vein graft (SVG) disease, we conducted a multicenter randomized placebo-controlled angiographic study of estradiol+/-medroxyprogesterone started within 6 months of CABG in 83 postmenopausal women. Angiographic and intravascular ultrasound (IVUS) assessment at 6 and 42 months was planned to assess SVG disease progression. The study was stopped early following publication of the Women's Health Initiative Estrogen/Progestin study. Eighty-three subjects underwent a 6-month angiogram with 63 undergoing IVUS. Forty-five subjects completed the 42-month angiogram (20 underwent 42-month IVUS). In analysis of paired 6- and 42-month angiogram and IVUS studies, HT slowed angiographic progression of SVG disease assessed by mean percent stenosis (p<0.001), minimal lumen diameter (p=0.029), and total plaque volume (p=0.006). In contrast, HT accelerated disease progression in non-bypassed native coronary arteries (minimum lumen diameter, p=0.01). SVG disease and closure occurred in 38% subjects within 1-year post-CABG. The groups had similar frequency of cardiovascular events expect for angioplasty that occurred in eight HT compared to one placebo subject (p<0.05). In HT subjects angioplasty was indicated for native coronary arterial stenoses while in the placebo subject angioplasty was indicated for SVG stenosis. This study suggests that hormone treatment may slow SVG disease progression while accelerating atherosclerosis in non-bypassed native coronary arteries.     

Primary stenting of occluded native coronary arteries: final results of the Primary Stenting of Occluded Native Coronary Arteries (PRISON) study

Background

Primary intracoronary stent placement after successfully crossing chronic total coronary occlusions may decrease the high restenosis rate at long-term follow-up compared with conventional balloon angioplasty.

Methods

In a prospective, randomized trial, balloon angioplasty was compared with stent implantation for the treatment of chronic total occlusions. Patients were followed for 12 months with angiographic follow-up at 6 months. Quantitative coronary analysis was performed by an independent core lab.

Results

A total of 200 patients were enrolled. Baseline characteristics were evenly distributed. After the procedure the mean minimal luminal diameter in the conventional group was 2.34 ± 0.46 mm versus 2.90 ± 0.41 mm in the stented group (P < .0001). The 6-month angiographic follow-up showed a mean minimal luminal diameter of 1.57 ± 0.74 mm in the conventional group versus 1.93 ± 0.85 mm in the stented group (P = .009) and a mean diameter stenosis of 44.7% ± 25.0% versus 35.5% ± 26.5% (P = .036). Binary angiographic restenosis (>50% diameter stenosis) was seen in 33% in the conventional group versus 22% in the stented group (P = .137). The reocclusion rates were 7.3% and 8.2%, respectively (P = 1.00). At 12 month follow-up, the rate of target lesion revascularization was significantly higher in the conventional group (29% versus 13%, P < .0001).

Conclusion

These data demonstrate that stenting of chronic total occlusions is superior to balloon angioplasty alone with a statistically significant reduction in the need for target lesion revascularization and a lower, but not significant, restenosis rate.