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.     

Hypersensitivity of human coronary segments to ergonovine 6 months after injury by coronary angioplasty: a quantitative angiographic study in consecutive patients undergoing single-vessel angioplasty

OBJECTIVE: Multiple studies have been designed to analyse restenosis angiographicallybut few have studied the vasoreactivity of coronary segmentssubjected to angioplasty a few months before. In the presentstudy we analysed, with use of quantitative angiography, thevasoreactivity of previously dilated segments to graded dosesof ergonovine and of isosorbide dinitrate. PATIENTS: Fifty consecutive patients undergoing follow-up angiography6 months after a single coronary angioplasty procedure werestudied. RESULTS: The vasoconstrictor response at dilated segments (–19·3±0·3%) was significantly greater than at controlproximal and distal sites in dilated (–7·3±1·1%,–11·0±2·9%) and non-dilated (–9·1±1·3%,–8·3±2·2%) vessels for the lowestdose of ergonovine (100 µg). The constrictor responseto 100 µg ergonovine (–20·2±5·3%)at restenosed segments (>50% stenosis, n=18) was similarto that (–18·8±3·8±) at non-restenosedsites (n=32). In contrast, the degree of constrictor responsewas similar in all segments including dilated segments for thehighest dose of ergonovine used. All segments dilated significantlyafter intracoronary injection of isosorbide dinitrate. CONCLUSION: Our results demonstrate hypersensitivity of the dilated siteto ergonovine 6 months after angioplasty at both restenosedand non-restenosed sites. This response may reflect partialdysfunction of endothelium that has regenerated after injuryor hypersensitivity of vascular smooth muscle cells at the siteof arterial injury.     

The reactivity of the contralateral artery at the time of balloon dilation during coronary angioplasty

The response of the contralateral arteries was investigatedduring balloon angioplasty of the left anterior descending artery.Thirty patients were studied. Coronary arteriograms were obtainedat baseline, during maximal balloon inflation and at the endof the procedure. Luminal diameter was measured by a quantitativecoronary arteriography analysis system. During balloon inflationthe luminal diameter of the proximal segment of the right coronaryartery increased by 24 ± 6% (P<0·05), and thatof the left circumflex artery increased by 0·6 ±6% (P=ns). Both returned to near baseline values after angioplasty.in patients with increased collaterals during balloon inflationthe left circumflex proximal segment increased more significantlythan in patients with unchanged collaterals. The luminal diameterof the distal segment of the right coronary artery increasedby 9 ± 8% (P<0·001) and that of the left circumflexartery by 8 ± 11% (P<0·01) during balloon inflation,returning to near baseline values after angioplasty. Thus, vasodilation of the contralateral arteries during ballooninflation at the time of coronary angioplasty occurs mainlyin the distal segments and appears to be related to an increasein collateral filling.     

Reactivity of proximal and distal angiographically normal and stenotic coronary segments in chronic stable angina pectoris

To assess whether vasoreactivity of significant coronary stenosis (greater than 50% intraluminal diameter reduction) and that of angiographically normal coronary segments differs in proximal and distal locations, 53 patients (40 men, 13 women, mean +/- standard deviation age 55 +/- 11 years) with chronic stable angina and angiographically documented coronary artery disease were studied. While abstaining from antianginal therapy, all 53 patients underwent coronary arteriography before and after 1 mg of intracoronary isosorbide dinitrate and 21 of the 53 also before and after 20 to 30 micrograms intracoronary ergonovine. Computerized quantitative angiography was used to assess changes in the intraluminal diameter of 126 normal coronary segments (63 proximal, 63 distal) and 43 significant coronary stenoses. Nitrates dilated proximal normal coronary segments by 7.4 +/- 1.2% and distal normal coronary segments by 15 +/- 1.7% (p less than 0.01). Significant proximal coronary stenoses dilated by 11 +/- 2.5% and distal stenoses by 23 +/- 2.8% (p less than 0.01) after nitrates. Ergonovine reduced the diameter of proximal normal coronary segments by 9.3 +/- 1.7% and that of normal distal segments by 15.5 +/- 1.4% (p less than 0.01). Proximal stenoses constricted by 11 +/- 2.2% and distal stenoses by 18.4 +/- 2.8% (p = 0.06). Analysis of segments showed that nitrates dilated 19 of 63 (30%) proximal normal segments by (greater than or equal to 10%), 31 of 63 (49%) distal (p less than 0.05) and 21 of 43 (49%) stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Iatrogenic coronary stenosis after angioplasty

Restenosis is the usual mechanism of recurrent myocardial ischaemia in the months following successful percutaneous transluminal coronary angioplasty (PTCA). Control coronary arteriography may occasionally show another cause: the constitution of a new stenosis near the dilated segment or in the left main coronary stem after angioplasty in a branch of this artery. The authors report 4 cases of patients who developed new coronary stenoses within a few weeks of PTCA, interpreted as traumatic complications of the initial procedure due to a lesion of the intima with a secondary fibrotic reaction and luminal narrowing. The guiding catheter was probably responsible for the trauma to the left main coronary stem whereas the tips of either the balloon catheter or the guide wire were thought to have been responsible for the endothelial effraction of the dilated vessels.     

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.     

Value of exercise radionuclide ventriculography and thallium-201 scintigraphy in evaluating successful coronary angioplasty: comparison with coronary flow reserve, translesional gradient and percent diameter stenosis

Assessment of percutaneous transluminal coronary angioplasty(PTCA) by early radionuclide exercise test was evaluated for11 arteries undergoing a successful procedure. Exercise thallium-201(Tl-201) and radio-nuclide ventriculography (RNV) were performedwithin 3 days before and after PTCA and compared to % diameterstenosis, % translesional gradient and regional coronary flowreserve (CFR) determined by digital coronary angiography. Primarysuccess of the procedure was gauged by reduction in % stenosisfrom 80 ± 12% to 31 ± 12% (residual stenosis <50% in all cases) and reduction in % gradient < 25% in allcases). Before PTCA, Tl-201 and/or RNV were abnormal in allcases. After PTCA, radionuclide exercise tests improved butremained abnormal in 4 instances. No relationship was foundbetween residual % gradient or stenosis and pathological Tl-201or RNV following PTCA, but abnormal tests were observed among4 out of the 5 vessels with the lowest CFR ( < 1.69). Inone case CFR remained depressed despite good angiographic, hemodynamicand scintigraphic results, this patient had unstable anginabefore the procedure. Among patients with stable symptoms, CFRof arterial distributions with positive Tl-201 or RNV afterPTCA was significantly lower than that with negative tests (1.58± 0.05 as compared to 1.90±0.25, P<0.02). Earlyradionuclide stress tests results thus reflect the physiologicimprovement of coronary circulation. They may reflect the persistenceof coronary flow abnormalities despite the relief of the epicardialstenosis.     

Blood flow velocity in the right coronary artery: Assessment before and after angioplasty

Objectives. This study attempted 1) to assess the utility of rest measurements of intracoronary blood flow velocity for the physiologic assessment of coronary stenoses before and after right coronary artery angioplasty, and 2) to compare the phasic flow pattern in the right coronary artery proper with the phasic flow pattern in its major branches to the left ventricle.Background. Previous investigations have demonstrated that a reduction in distal blood flow velocity and a loss of distal diastolic predominant flow are characteristic of physiologically significant stenoses and that these indexes normalize after successful coronary artery dilation. However, these studies were predominantly performed in the left coronary artery. The utility of monitoring rest velocity variables during angioplasty of the right coronary artery has not been studied.Methods. We studied 20 patients undergoing angioplasty of the right coronary artery with use of a Doppler angioplasty guide wire.Results. Values were expressed as the mean value ± 1 SD. The rest average peak velocity did not decrease distal to angiographically significant right coronary artery stenoses (23.3 ± 9.4 cm/s proximal vs. 20.2 ± 11.1 cm/s distal, p = 0.20). The proximal/ distal velocity ratio was 1.4 ± 0.9 before angioplasty and did not significantly decrease after angioplasty (p = 0.58). This study had a 99.4% power to detect a difference between proximal and distal average peak velocity. There was no relation between percent diameter stenosis and proximal/distal velocity ratios (r = 0.15, p = 0.55). Diastolic predominant flow was not observed in the proximal or distal right coronary artery. However, after angioplasty, diastolic predominant flow was observed in the posterolateral and posterior descending coronary arteries.Conclusions. Rest phasic Doppler flow velocity indexes are not useful for evaluating stenoses in the right coronary artery proper before or after angioplasty. In contrast to the right coronary artery proper, diastolic predominant flow is observed in the posterior descending and posterolateral coronary arteries. The utility of measuring hyperemic Doppler flow velocity indexes, such as distal coronary flow reserve, for assessing right coronary artery stenoses merits further investigation.     

Coronary Vasomotion After Percutaneous Transluminal Coronary Angioplasty Depends on the Severity of the Culprit Lesion

Objectives. This study sought to evaluate coronary vasomotor response to percutaneous transluminal coronary angioplasty (PTCA) and its influence on proximal and distal vessel diameters with regard to stenosis severity and coronary blood flow.Background. Coronary vasoconstriction of the distal vessel segment has been reported after PTCA. This vasoconstrictive effect was thought to be due to balloon-induced injury of the vessel wall, with release of local vasoconstrictors or stimulation of the sympathetic system with release of catecholamines, or both.Methods. Thirty-nine patients were prospectively studied before and after PTCA. Patients were classified into two groups according to the severity of the culprit lesion: group 1= ≥70% to ≤85% diameter stenosis (n = 23); and group 2= >85% to ≤95% diameter stenosis (n = 16). The coronary vessel diameter of the proximal and distal vessel segments as well as the minimal lumen diameter were determined by quantitative coronary angiography. In a subgroup of 16 patients, basal and maximal coronary flow velocity was measured before and after PTCA with the Doppler FloWire system.Results. The groups were comparable with regard to age, gender, serum cholesterol levels and medical therapy. The proximal vessel segment remained unchanged after PTCA in group 1 ([mean ± SD] 0.9 ± 3.5%, p = 0.8) but showed vasodilation in group 2 (+13.7 ± 3.6%, p < 0.05). However, the distal segment showed vasoconstriction in group 1 (−6.7 ± 2.0%, p < 0.01) and vasodilation in group 2 (+31 ± 8.0%, p < 0.01). A significant correlation was found between the change in distal vessel diameter after PTCA and stenosis severity (r = 0.61, p < 0.0001). Changes in blood flow were directly correlated to stenosis severity (r = 0.85, p < 0.002); that is, rest flow increased after PTCA in narrow lesions but remained unchanged in moderate lesions. The diameter changes in the distal vessel segment after PTCA were significantly related to flow changes (r = 0.90, p < 0.0001). Coronary distending pressure of the distal vessel segment increased significantly in both groups; however, this increase was significantly greater in group 2 than in group 1 (55 ± 4 vs. 14 ± 3 mm Hg, p < 0.0001).Conclusions. Coronary vasomotion of the proximal and distal vessel segments after PTCA depends on the severity of the culprit lesion; that is, vasoconstriction of the distal segment is found in patients with moderate lesions and vasodilation in those with severe lesions. Thus, vasomotion of the post-stenotic vessel segment depends on the severity of the culprit lesion and is influenced by changes in coronary flow or distending pressure, or both.     

Clinical significance of residual collaterals immediately after successful coronary angioplasty.

The clinical significance of collaterals visible on angiography immediately after successful percutaneous transluminal coronary angioplasty (PTCA) was analyzed in 221 patients who underwent successful PTCA for coronary arteries receiving collaterals. Filling of the collaterals was classified as good; filling the entire epicardial segment of the stenosed site, fair; partially filling the epicardial segments distal to the stenosed site, and faint; visible but not filling the epicardial segments of the diseased vessel. Fifteen of 41 good collaterals remained good or fair on angiography immediately after PTCA. Among the 114 fair collaterals, 26 remained fair and 20 of 66 faint collaterals remained visible on the angiogram immediately after PTCA. There was no relationship between the degree of residual stenosis after PTCA and the degree of residual collaterals. Repeat coronary angiography was obtained in 156 patients. There was no correlation between the presence, absence or degree of collaterals observed on angiography immediately after successful PTCA and the rate of restenosis. Thus, collaterals to the vessels dilated by PTCA often remain on the angiogram immediately after PTCA and are dependent primarily on their degree before dilation. They do not indicate inadequate dilation or predict restenosis.     

Endothelium-dependent and endothelium-independent vasomotion in large coronary arteries and in the microcirculation after cardiac transplantation

Endothelium-dependent and endothelium-independent vasodilationof the epicardial conduit vessels and the microcircu-latorycoronary vessels was investigated with cumulative doses of acetylcholine(ACh 50µg and 100µg i.e.), nitroglycerin (0.3 mgi.e.) and dipyridamole (0.56mg. kg^–1 i.v.) in 17 patients(3 female114 male; age: 47±3.6 years) with angiographicallynormal coronary arteries 40 ± 51 months after cardiactransplantation. The effect of ACh on large conduit arterieswas evaluated angiographically. Coronary blood flow velocitychanges were measured utilizing an 8F Judkins style 20 MHz Dopplercatheter positioned in the left main coronary artery. A coronaryflow index was calculated from the mean Doppler flow velocityand the computed cross-sectional vascular area. After 50 µgof ACh the diameter of proximal, middle and distal segmentsof the left anterior descending coronary artery decreased significantlyby 7.6±2.06% (P<0.05), 10.6 ±3.5% (P<001)and 12.6±3.29% (P<0.01) and after 100 µg AChby 10.5 ±2.4% (P<0.05), 13.0 ±3.7% (P<001)and 15.3 ±3.9% (P<001). The endothelium-independentvasodilator nitroglycerin (0.3 mg i. e.) induced an increasein vascular diameter of 14.4±31% (P<001), 18.6±4.1%(P<001) and 20.8 ± 2.9% (P<0.01) in proximal, midand distal segments of the left anterior descending coronaryartery. In the circumflex branch the diameter of proximal, middleand distal vascular segments decreased after 50 µg ofACh by 5.1 ±2.7% (P<005), 9.5 ±2.6% (P<001)and 8.8 ±3.27% (P<005) and after 100µg by 9.9±2.5% (P<001), 11.1 ±3.7% (P<001) and 10.8±3.8% (P<0.01). An increase of 17.4 ±3.5% (P<001),20.7 ±3.4% (P<001) and 26.2 ± 3.4% (P<001)was noted after nitroglycerin. Coronary flow index increased after 50 µg of ACh by 133±23% (P<0.01) and after 100 µg by 106.8± 29.8%(P<0.05). The endothelium-independent microcirculatory vasodilator,dipyridamole, caused an increase of coronary flow index of 165.2±36.1%(P<0.01). In conclusion, the ACh-induced decrease in conduit coronaryartery diameter suggests that endothelial dysfunction couldresult long-term after cardiac transplantation, whereas endothelium-independentvasodilation after nitroglycerin is preserved Additionally,the vasodilatory response of the microcirculation to stimulationby ACh is reduced in the long-term after cardiac transplantation,as is endothelium-independent vasodilation after dipyridamole.     

Discrepancy between visual estimation and computer-assisted measurement of lesion severity before and after coronary angioplasty

One hundred fourteen coronary stenoses were quantified before and after percutaneous transluminal coronary angioplasty (PTCA) using a semi-automated digital system. The values obtained were considered as standard for comparison with visual estimation by the PTCA operator as well as by independent consensus-reading. The measured percent stenosis was 62.7 ± 13.7% before and 27.7 ± 12.4% after angioplasty. Before PTCA, the operator consistently overestimated stenosis severity (87.8 ± 8.5%, P < 0.0001) and consensus-reading reduced but did not eliminate this overestimation (78.0 ± 12.3%, P < 0.05). The error in visual estimation was inversely correlated with the measured degree of stenosis: coefficients were –0.79 (P < 0.0001) and –0.51 (P < 0.0001) for operator and consensus-readers, respectively. After PTCA, the operator underestimated the residual stenosis (21.2 ± 9.9%, P < 0.0001) but there was no systematic bias by consensusreading (29.4 ± 12.0%, NS). Again the error in visual estimation was inversely correlated with the measured degree of residual stenosis : coefficients were –0.76 (P < 0.0001) and –0.58 (P < 0.0001) for operator and consensus-reading, respectively. In conclusion, the operator overestimates lesion severity before and underestimates moderate residual stenoses after PTCA, a problem only partially corrected by independent consensus-readers.     

Clinical experience with the use of the angled-balloon dilatation catheter

A special balloon catheter has been developed for use in coronary angioplasty. The balloon portion has a 135 degrees - 145 degrees angle at its mid portion. It is designed for stenosis located at an angle of the coronary artery. We investigated the use of this catheter in 39 patients who underwent percutaneous transluminal coronary angioplasty (PTCA): 29 men and 10 women. PTCA was attempted in 43 stenotic sites. Thirty-two stenoses were located at the angled portion of the dilated arteries. Eleven stenoses were located at the side branches of the acutely angled bifurcations. Twenty stenoses were in the right coronary artery distribution. Twenty-two stenoses were in the left coronary artery distribution. One stenosis was at the origin of the left internal mammary artery. Forty-one stenoses were angioplastied successfully (95.4%). No angiographic evidence of intimal tear or dissection was noted in all of the dilated vessels. Acute closure was not observed. The mean follow-up period was 239.5 days. Six patients (15.4%) were found to have restenosis. We conclude that the use of the angled-balloon dilatation catheter provides the potential benefit of reducing intimal trauma and dissection during PTCA of certain coronary anatomies--stenosis at the angled portion or at the takeoff of the side branch of a bifurcation.     

Cutting balloon coronary angioplasty—initial clinical experience

The success of percutaneous transluminal coronary angioplasty is limited by acute occlusion and late restenosis. In 25 patients (20 men, 5 women, age range 36–81 years) coronary angioplasty was performed using a new cutting balloon into which 3–4 longitudinally orientated blades are incorporated so as to reduce the rate of severe dissections. In 12 patients stenoses were reduced from 83.9 ± 7.8% to 28.4 ± 10.7% (mean ± SD) by the cutting balloon alone, using predilatation with a small conventional balloon in two cases. Thirteen other patients were additionally dilated with a conventional balloon because of a residual stenosis > 50% after cutting balloon angioplasty. Here the stenoses could be reduced from 78.1 ± 8.7% to 29.1 ± 11.3%. Six months follow-up angiography in 14 patients showed > 50% restenosis in two of seven patients dilated with a conventional balloon in addition to the cutting balloon, and in one of seven patients dilated with the cutting balloon alone but predilated with a small conventional balloon. These results show that coronary angioplasty by the new cutting balloon results in a stenosis reduction comparable with conventional balloons at a low complication rate. Available 6 months follow-up data show three restenoses in patients either pre- or postulated by a conventional balloon and none in stand-alone cutting balloon cases.     

Alterations of phasic coronary artery flow velocity in humans during percutaneous coronary angioplasty.

BACKGROUND AND OBJECTIVES. Studies using Doppler catheters to assess blood flow velocity and vasodilator reserve in proximal coronary arteries have failed to demonstrate significant improvement immediately after coronary angioplasty. Measurement of blood flow velocity, flow reserve and phasic diastolic/systolic velocity ratio performed distal to a coronary stenosis may provide important information concerning the physiologic significance of coronary artery stenosis. This study was designed to measure these blood flow velocity variables both proximal and distal to a significant coronary artery stenosis in patients undergoing coronary angioplasty. METHODS. A low profile (0.018-in.) (0.046-cm) Doppler angioplasty guide wire capable of providing spectral flow velocity data was used to measure blood flow velocity, flow reserve and diastolic/systolic velocity ratio both proximal and distal to left anterior descending or left circumflex coronary artery stenosis. These measurements were made in 38 patients undergoing coronary angioplasty and in 12 patients without significant coronary artery disease. RESULTS. Significant improvement in mean time average peak velocity was noted in distal coronary arteries after angioplasty (before 19 +/- 12 cm/s; after 35 +/- 16 cm/s; p less than 0.01). Increases in proximal average peak velocity after angioplasty were less remarkable (before 34 +/- 18 cm/s; after 41 +/- 14 cm/s; p = 0.04). Mean flow reserve remained unchanged after angioplasty both proximal (1.5 +/- 0.5 vs. 1.6 +/- 1; p greater than 0.10) and distal (1.6 +/- 1 vs. 1.5 +/- 0.8; p greater than 0.10) to a coronary stenosis. Before angioplasty, mean diastolic/systolic velocity ratio measured distal to a significant stenosis was decreased compared with that in normal vessels (1.3 +/- 0.5 vs. 1.8 +/- 0.5; p less than 0.01). After angioplasty, distal abnormal phasic velocity patterns generally returned to normal, with a significant increase in mean diastolic/systolic velocity ratio (1.3 +/- 0.5 vs. 1.9 +/- 0.6; p less than 0.01). Phasic velocity patterns and mean diastolic/systolic velocity ratio measured proximal to a coronary stenosis were not statistically different from values in normal vessels (1.8 +/- 0.8 vs. 1.8 +/- 0.5; p greater than 0.10) and did not change significantly after angioplasty (1.8 +/- 0.8 vs. 2.13 +/- 0.9; p greater than 0.10). CONCLUSIONS. Flow velocity measurements may be performed distal to a coronary stenosis with the Doppler guide wire. Phasic velocity measurements made proximal to a coronary stenosis differed from those in the distal coronary artery. Both proximal and distal flow reserve measurements made immediately after angioplasty were of limited utility. Changes in distal flow velocity patterns and diastolic/systolic velocity ratio appeared to be more relevant than the hyperemic response in assessing the immediate physiologic outcome of coronary angioplasty.     

Assessment of regional myocardial perfusion with thallium imaging during transient left anterior descending coronary arterial occlusion during angioplasty

To define the jeopardized territory perfused through a single coronary arterial stenosis, thallium-201, 2 mCi, was injected into the pulmonary artery at the onset of the last of a series of percutaneous transluminal coronary angioplasty (PTCA) balloon inflations in 10 patients with single-vessel left anterior descending coronary artery disease. Imaging was begun immediately after PTCA. Arterial thallium activity peaked 30 seconds after injection and decreased to 34 ± 6% (mean ± standard error of the mean) of peak activity at the time of balloon deflation. Regional thallium activity during exercise vs PTCA was scored qualitatively and quantitatively. A computer quantification program was used that permitted automatic realignment and normalization of the 2 initial thallium images. Only mean quantitative posterior activity was lower (93 ± 1% vs 86 ± 2%, p < 0.05) on exercise scans compared with PTCA scans. The other 5 segments showed no difference in mean scores. There were no qualitative differences in initial thallium distribution, nor were there qualitative or quantitative differences in the number of abnormal segments or severity of reduction in activity in the segment with the lowest activity. In conclusion, regional thallium myocardial distribution with a single severe stenoses with injection during peak exercise is similar to that after complete coronary occlusion.     

Endothelium dependent and independent responses in coronary artery disease measured at angioplasty.

OBJECTIVE--To investigate the effects of substance P and papaverine, two drugs that increase coronary blood flow by different mechanisms, on vasomotion in stenotic coronary arteries at percutaneous transluminal coronary angioplasty (PTCA). DESIGN--Coronary blood flow responses to substance P and papaverine were measured in stenotic coronary arteries at the time of PTCA with quantitative angiography and a Doppler flow probe. SETTING--A cardiothoracic referral centre. PATIENTS--15 patients undergoing elective PTCA of a discrete epicardial coronary artery stenosis. INTERVENTIONS--Pharmacological coronary flow reserve was determined with papaverine 5-10 minutes before and after successful PTCA. Endothelium dependent responses to 2 minute infusions of substance P (10-15 pmol.min-1) were assessed immediately before PTCA. MAIN OUTCOME MEASURES--Coronary blood flow responses and changes in epicardial coronary artery area at stenotic, proximal, and distal sites with papaverine and substance P. RESULTS--Stenotic sites dilated with papaverine before PTCA (17.7%(6.9%) (mean (SEM)) area increase, p < 0.05 v baseline). Substance P dilated stenotic sites (16.8%(5.7%) area increase, p < 0.05) and proximal (14.3%(5.4%), p < 0.05) and distal sites (41.7%(9.3%), p < 0.005). Coronary flow reserve increased but did not reach normal values after PTCA (2.3(0.4) before PTCA v 3.0(0.4) after PTCA, p < 0.05) and was associated with an increase in peak flow with papaverine. Angioplasty did not alter baseline flow. After PTCA papaverine caused significant vasoconstriction at the stenotic site (-13.6%(4.3%) area decrease, p < 0.05). There was a negative correlation (r = -0.68, p < 0.05) between the dilator response with papaverine before PTCA and the constrictor response after PTCA. CONCLUSIONS--Substance P causes endothelium dependent dilatation in atheromatous coronary arteries, even at sites of overt atheroma. The cause of the paradoxical constrictor response to papaverine after PTCA is uncertain, but unopposed flow mediated vasoconstriction (the myogenic response) after balloon induced endothelial denudation may be one of several contributory factors.     

Safety of deferring angioplasty in patients with normal coronary flow velocity reserve

Background. In the catheter laboratory there is a need for functional tests validating the hemodynamic significance of coronary artery stenosis.Objectives. It was the objective of our study to compare the long-term cardiac event rate and the clinical symptoms in patients with reduced coronary flow velocity reserve (CFVR) and standard PTCA with patients with normal CFVR and deferred angioplasty.Methods. Our study included 70 patients with intermediate coronary artery stenoses (13 f, 57 m; diameter stenosis >50%, <90%) and an indication for PTCA due to stable angina pectoris and/or signs of ischemia in noninvasive stress tests. CFVR was measured distal to the lesion after intracoronary administration of adenosine using 0.014 inch Doppler-tipped guide wires.Results. In 22 patients (31%), PTCA was deferred due to a CFVR ≥ 2.0 (non-PTCA group). In the remaining 48 patients (69%) mean CFVR of 1.4 ± 0.23 (p < 0.001) was measured (PTCA group). CFVR increased to 2.0 ± 0.51 after angioplasty. During follow-up (average 15 ± 6.0 months), the following major adverse cardiac events (MACE) occurred: in the PTCA group re-PTCA was performed in nine patients (18.8%) because of unstable angina, five patients (10.4%) suffered an acute myocardial infarction (MI) (two infarctions occurred during the angioplasty, three patients suffered an infarction during follow-up), two patients (4.2%) needed blood transfusions due to severe bleedings, two patients (4.2%) underwent bypass surgery and one patient (2.1%) died. In the non-PTCA group, angioplasty was necessary only in two cases (9.1%) during follow-up. We did not observe any MI in the non-PTCA group.The overall rate of MACE was significantly lower in the non-PTCA group compared to the PTCA group (9.1% vs. 33.3%, p < 0.01). However, only 40% of the patients of the non-PTCA group were free of angina pectoris at stress. In the PTCA group, 63% did not complain of any symptoms at follow-up (p < 0.05).Conclusions. We conclude that determination of the CFVR is a valuable parameter for stratifying the hemodynamic significance of coronary artery stenosis. PTCA can safely be deferred in patients with significant coronary stenosis but a CFVR ≥ 2.0. The total rate of MACE at follow-up was below 10% among these patients. However, if PTCA was deferred the number of patients who are free of angina is lower compared to those patients who underwent angioplasty.     

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.     

Does percutaneous transluminal coronary angioplasty accelerate atherosclerotic lesions?

Recent reports have suggested that angioplasty may cause or accelerate coronary arterial stenoses secondary to traumatic injury. Ninety-four coronary angiograms performed in a 1 yr period were reviewed in patients who had successful coronary angioplasty 6 to 30 mo (mean 10.7) prior to restudy. Restenosis was found in 43 of 140 dilated lesions (31%) and in 41 of 94 patients (44%). Thirty-three (35%) patients had new or progressive lesions outside the angioplasty site. New or progressive lesions occurred with similar frequency in the arteries that did not have angioplasty (23/155 = 15%) as in the arteries that did (13/127 = 10%; chi-square n.s.). In the arteries which underwent angioplasty, new or progressive lesions occurred as commonly proximal to the PTCA site (7/14, 50%) as distal (6/13, 46%). New or progressive lesions occurred in 29% of patients with concomitant restenosis, and 40% of those without restenosis (chi-square n.s.). No clinical, angiographic, or procedural factors distinguished patients with new and progressive lesions in target vessels from those without these lesions in target vessels. Patients with progressive lesions anywhere in the coronary tree were more likely to have had a shorter duration of anginal symptoms before angioplasty and a family history of coronary disease when compared with patients without progressive atherosclerosis. In conclusion, new and progressive lesions outside the angioplasty site occur after the procedure but appear unrelated to the restenosis process or traumatic injury by angioplasty instrumentation.