Sensitivity of ovine myometrial tissue to various eicosanoids in vitro

The sensitivity of sheep myometrial tissue to prostaglandin F2 alpha (PGE2 alpha), PGE2, the thromboxane analog U-44069, and leukotrienes C4 (LTC4) and LTD4 was investigated in a superfusion system. Tissues were obtained from eight oophorectomized ewes, with or without pretreatment with estradiol-17 beta. After equilibration, spontaneous activity was abolished by adding indomethacin to the superfusion fluid. The dose needed to induce a contraction with a peak level of 50% of the median peak level of spontaneous contractions increased from PGE2 to PGF2 alpha, U-44069, LTC4, and LTD4. The differences between the doses required were significant for all compounds, except between LTC4 and LTD4. Estradiol-17 beta pretreatment caused an increase in the required dose of PGF2 alpha. The results of this study do not support the hypothesis that leukotrienes are involved in the regulation of myometrial activity.

Primary coronary angioplasty versus intravenous streptokinase in acute myocardial infarction: differences in outcome during a mean follow-up of 18 months

BACKGROUND

Intravenous streptokinase and primary coronary angioplasty are both considered to be effective treatment strategies for patients with acute myocardial infarction. Although primary coronary angioplasty is associated with a high patency rate and a well-preserved left ventricular function, it is not known whether it results in a more favorable clinical outcome in randomized comparisons.

METHODS

Clinical data were obtained after a mean follow-up of 18 months (range 6-36 months) after random allocation of 301 patients either to intravenous streptokinase (n = 149) or to primary angioplasty (n = 152). The primary endpoint includes death from cardiac causes and non-fatal reinfarction. The secondary endpoint is a weighted unsatisfactory outcome, one that includes death, stroke, heart failure, shock, ejection fraction lower than 30%, reinfarction, reocclusion and bleeding complications. The need for revascularization procedures was recorded.

RESULTS

The relative risk of death from cardiac causes and non-fatal reinfarction in the streptokinase group was 6.1 (95% confidence interval 2.9-12.7) compared with the angioplasty group. There was a lower weighted unsatisfactory outcome score of 0.13 +/- 0.29 in patients randomly assigned to angioplasty compared with 0.34 +/- 0.33 in patients randomly assigned to streptokinase (P < 0.001). Coronary angioplasty or coronary artery bypass grafting, or both, were performed more often in the streptokinase group, with a relative risk of 2.1 compared with patients randomly assigned to angioplasty (95% confidence interval 1.5-3.2).

CONCLUSION

Clinical outcome in patients with acute myocardial infarction after a mean follow-up of 18 months was more favorable in patients randomly assigned to primary angioplasty compared with those receiving intravenous streptokinase.

Limitation of infarct size and preservation of left ventricular function after primary coronary angioplasty compared with intravenous streptokinase in acute myocardial infarction

BACKGROUND

Early and effective flow through the infarct-related vessel is probably of paramount importance for limitation of infarct size and preservation of left ventricular function in patients with acute myocardial infarction. Primary coronary angioplasty may offer advantages in these respects compared with thrombolytic therapy. The purpose of the present study was to assess the effects on estimated enzymatic infarct size and left ventricular function in patients with acute myocardial infarction randomly assigned to undergo primary angioplasty or to receive intravenous streptokinase.

METHODS AND RESULTS

We evaluated 301 patients with signs of acute myocardial infarction and without contraindications for thrombolysis who presented within 6 hours after onset of symptoms or between 6 and 24 hours if there was evidence of ongoing ischemia. One hundred fifty-two patients were randomly assigned to undergo primary angioplasty, and 149 patients were assigned to receive treatment with streptokinase (1.5 million U i.v.). Infarct size was estimated from enzyme release. Global left ventricular ejection fraction and regional wall motion, if possible in combination with exercise testing, were evaluated by radionuclide ventriculography before discharge. Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 through the infarct-related vessel within 120 minutes after admission was achieved in 92% of all patients assigned to receive primary angioplasty therapy. Myocardial infarct size was 23% smaller in the angioplasty group compared with patients assigned to receive streptokinase (1003 +/- 784 versus 1310 +/- 1198 U/L, P = .012). Global left ventricular ejection fraction (50 +/- 9% versus 45 +/- 11%, P < .001) and regional wall motion in the infarct-related zones (42 +/- 14% versus 34 +/- 13%, P < .001) were better in the angioplasty group, which could mainly be contributed to myocardial salvage in the infarct-related areas. The observed differences were more pronounced in patients with an anterior wall myocardial infarction, although patients with a nonanterior infarct location also showed a beneficial effect of primary coronary angioplasty on left ventricular function compared with streptokinase therapy. Furthermore, the observed differences appeared to be more pronounced in patients presenting relatively early (within 2 hours) after onset of symptoms.

CONCLUSIONS

In patients with acute myocardial infarction, primary angioplasty results in a smaller infarct size and a better preserved myocardial function compared with patients randomized to receive treatment with intravenous streptokinase. This is probably due to early and optimal blood flow through the infarct-related vessel, as can be accomplished in a very high percentage of patients undergoing primary coronary angioplasty.

Immediate coronary angioplasty versus intravenous streptokinase in acute myocardial infarction: left ventricular ejection fraction, hospital mortality and reinfarction

OBJECTIVES

The purpose of the present study was to compare intravenous streptokinase therapy with immediate coronary angioplasty without antecedent thrombolytic therapy with regard to left ventricular function and hospital mortality and reinfarction.

BACKGROUND

Despite the widespread use of intravenous thrombolytic therapy and immediate percutaneous transluminal coronary angioplasty, these two strategies to treat patients with an acute myocardial infarction have only recently been compared in randomized trials. Coronary angioplasty has been shown to result in a higher patency rate of the infarct-related coronary artery, with a less severe residual stenotic lesion, compared with streptokinase therapy, but whether this more favorable coronary anatomy results in clinical benefit remains to be established.

METHODS

We studied 301 patients with acute myocardial infarction randomly assigned to undergo immediate coronary angioplasty without antecedent thrombolytic therapy or to receive intravenous streptokinase therapy. Before discharge left ventricular ejection fraction was measured by radionuclide scanning.

RESULTS

The in-hospital mortality rate in the streptokinase group was 7% (11 of 149 patients) compared with 2% (3 of 152 patients) in the angioplasty group (p = 0.024). In the streptokinase group recurrent myocardial infarction occurred in 15 patients (10%) versus in 2 (1%) in the angioplasty group (p < 0.001). Either death or nonfatal reinfarction occurred in 23 patients (15%) in the streptokinase group and in 5 patients (3%) in the angioplasty group (p = 0.001). Left ventricular ejection fraction was 44 +/- 11% (mean +/- SD) in the streptokinase group versus 50 +/- 11% in the angioplasty group (p < 0.001).

CONCLUSIONS

These findings indicate that immediate coronary angioplasty without antecedent thrombolytic therapy results in better left ventricular function and lower risk of death and recurrent myocardial infarction than treatment with intravenous streptokinase.

Predictive value of reactive hyperemic response on reperfusion on recovery of regional myocardial function after coronary angioplasty in acute myocardial infarction

BACKGROUND

The objective of the study was to determine the coronary vasodilatory reserve in reperfused myocardium in patients with acute myocardial infarction and its relation to regional myocardial function.

METHODS AND RESULTS

The study population consisted of 22 patients with acute myocardial infarction who underwent successful coronary angioplasty. The vasodilatory reserve in the reperfused myocardium was assessed quantitatively using computer-assisted digital subtraction cine-angiography immediately after angioplasty and at follow-up angiography before hospital discharge. Myocardial contrast medium appearance time and density were determined before and after pharmacological hyperemia induced by an intracoronary injection of 12.5 mg papaverine. Global and regional left ventricular functions were determined from contrast angiography. After papaverine, the mean contrast medium appearance time decreased significantly from 3.5 +/- 0.7 to 2.7 +/- 0.7 cardiac cycles (P < .000005) immediately after successful coronary angioplasty and from 3.8 +/- 0.7 to 2.7 +/- 0.9 cardiac cycles (P < .000005) at angiography before hospital discharge. The mean contrast medium density increased significantly from 48.7 +/- 13.8 to 61.0 +/- 19.0 pixels (P < .003) and from 49.6 +/- 19.7 to 80.3 +/- 29.6 pixels (P < .000005), respectively. As a consequence, the calculated coronary flow reserve increased significantly from 1.8 +/- 0.7 to 2.6 +/- 1.0 (P < .0008). The global ejection fraction increased significantly from 52 +/- 12% to 58 +/- 14% (P < .03), primarily because of a significant improvement in the regional myocardial function of the infarct zone from 20.8 +/- 9.0% to 26.0 +/- 10.5% (P < .001). Coronary flow reserve correlated well with regional myocardial function both during the acute phase (R = .79, P < .002) and at follow-up angiography (R = .82, P < .000004). Interestingly, coronary flow reserve measurement on reperfusion, immediately after angioplasty, correlated significantly with regional myocardial function at follow-up angiography (R = .81, P < .00003).

CONCLUSIONS

The results indicate that there is a pharmacologically inducible vasodilatory reserve in reperfused ischemic myocardium after successful coronary angioplasty in patients with acute myocardial infarction and that this is increased at 10-day follow-up angiography. More important, the degree of reactive hyperemic response on reperfusion has a predictive value regarding the ultimate degree of recovery of regional myocardial function. Quantitative assessment of reperfusion may be useful in investigating the role of coronary reperfusion and salvage of myocardial function.

Usefulness of repeat coronary angiography 24 hours after successful balloon angioplasty to evaluate early luminal deterioration and facilitate quantitative analysis

Because of the unavoidable occurrence of vessel disruption after successful coronary balloon angioplasty, the reliability of quantitative angiographic analysis in that setting has been questioned. For this reason and the suggested occurrence of delayed elastic recoil, repeat angiography at 24 hours has been advocated in clinical interventional trials. In this study, these issues are confronted by performing comprehensive quantitative analysis (Cardiovascular Angiographic Analysis System) of coronary angiograms, acquired in multiple identical projections immediately after and 24 hours after angioplasty, in 102 patients with 110 successfully dilated lesions. Vasomotion was controlled by intracoronary nitrate before angiography and all patients were fully anticoagulated (activated partial thromboplastin time 85 to 120 seconds) for > 24 hours. Paired Student's t tests applied to angiographic measurements revealed that there was no significant deterioration in minimal luminal diameter or cross-sectional area from immediately after angioplasty to 24 hours later. It can thus be inferred that there is no phenomenon of delayed elastic recoil, at least during this time period. Measurement accuracy and precision of the Cardiovascular Angiographic Analysis System from the postangioplasty angiogram are highly acceptable, at < 0.01 and +/- 0.20 mm, respectively. Therefore, it is concluded that routine repeat 24-hour angiography is not indicated after successful angioplasty. A highly significant increase (p < 0.001) in reference diameter (+0.11 +/- 0.18 mm) was responsible for the apparent increase in percent diameter stenosis (2.4 +/- 7%), a finding that demonstrates the potential for error by selective application of percent diameter stenosis measurements alone. Preferential use of absolute luminal measurements is thus strongly recommended for clinical trials with angiographic monitoring.

Safety and efficacy of recombinant hirudin (CGP 39 393) versus heparin in patients with stable angina undergoing coronary angioplasty

BACKGROUND

Enhanced thrombin activity has been associated with acute and long-term complications following balloon angioplasty (percutaneous transluminal coronary angioplasty (PTCA). We evaluated, in a 2-to-1 randomized, double-blind trial, the effects of recombinant hirudin, CGP 39 393, relative to unfractionated sodium heparin on periprocedural events, bleeding, early angiographic outcome, and coagulation in 113 patients with stable angina undergoing PTCA.

METHODS AND RESULTS

Prior to PTCA, 20 mg CGP 39 393 was administered as a bolus, followed by continuous infusion at a rate of 0.16 mg.kg-1 x h-1, or 10,000 IU sodium heparin was administered as a bolus and continued at a rate of 12 IU.kg-1 x h-1 for 24 hours. Infusion was adjusted to activated partial thromboplastin time (APTT) levels. ST segment was monitored for 24 hours, and angiograms were analyzed with quantitative technique (QCA). In 74 CGP 39 393- and 39 heparin-treated patients, 132 lesions were dilated. Myocardial infarction and/or emergency coronary bypass surgery occurred in 1 (1.4%) CGP 39 393 patient compared with 4 (10.3%) heparin patients (relative risk, 7.6; 95% confidence interval, 0.9, 65.6). At 24 hours, complete perfusion was present in 91% heparin and 100% CGP 39 393 patients. Significant ST segment displacement was found in 11% of heparin versus 4% of CGP 39 393 subjects. Bleeding occurred only at the puncture site in 4 CGP 39 393-treated patients. QCA did not reveal significant differences between the groups. APTT values were more often in the target range and more stable in CGP 39 393 patients. Levels of thrombin-antithrombin III complexes, prothrombin fragment F1+2, and fibrinopeptide A indicated that CGP 39 393 was an effective inhibitor of thrombin activity.

CONCLUSIONS

CGP 39 393 can safely be administered to patients undergoing elective PTCA for stable anginal symptoms and may have a more favorable anticoagulant profile than heparin.

A comparison of immediate coronary angioplasty with intravenous streptokinase in acute myocardial infarction

BACKGROUND

Despite the widespread use of intravenous thrombolytic therapy and of immediate percutaneous transluminal coronary angioplasty for the treatment of acute myocardial infarction, randomized comparisons of the two approaches to reperfusion are lacking. We report the results of a prospective, randomized trial comparing immediate coronary angioplasty (without previous thrombolytic therapy) with intravenous streptokinase treatment.

METHODS

A total of 142 patients with acute myocardial infarction were randomly assigned to receive one of the two treatments. The left ventricular ejection fraction was measured by radionuclide scanning before hospital discharge. Quantitative coronary angiography was performed to assess the degree of residual stenosis in the infarct-related arteries.

RESULTS

A total of 72 patients were assigned to receive streptokinase and 70 patients to undergo immediate angioplasty. Angioplasty was technically successful in 64 of the 65 patients who underwent the procedure. Infarction recurred in nine patients assigned to receive streptokinase, but in none of those assigned to receive angioplasty (P = 0.003). Fourteen patients in the streptokinase group had unstable angina after their infarction, but only four in the angioplasty group (P = 0.02). The mean (+/- SD) left ventricular ejection fraction as measured before discharge was 45 +/- 12 percent in the streptokinase group and 51 +/- 11 percent in the angioplasty group (P = 0.004). The infarct-related artery was patent in 68 percent of the patients in the streptokinase group and 91 percent of those in the angioplasty group (P = 0.001). Quantitative coronary angiography revealed stenosis of 36 +/- 20 percent of the luminal diameter in the angioplasty group, as compared with 76 +/- 19 percent in the streptokinase group (P < 0.001).

CONCLUSIONS

Immediate angioplasty after acute myocardial infarction was associated with a higher rate of patency of the infarct-related artery, a less severe residual stenotic lesion, better left ventricular function, and less recurrent myocardial ischemia and infarction than was intravenous streptokinase.

Separate origin of a large septal perforator branch

A patient with an inferior myocardial infarction was successfully treated with thrombolytic therapy. At selective coronary arteriography a large septal perforator branch originating from the right coronary sinus anastomosing to the proximal left anterior descending coronary artery was seen. As far as we know, this has never been described before.

A comparison of two methods to measure coronary flow reserve in the setting of coronary angioplasty: intracoronary blood flow velocity measurements with a Doppler catheter, and digital subtraction cineangiography

Intracoronary blood flow velocity measurements with a Doppler balloon catheter and the radiographic assessment of myocardial perfusion with contrast media, before and after the intracoronary administration of papaverine, have previously been used to investigate regional coronary flow reserve. In the present study we applied both techniques in 21 patients to measure coronary flow reserve in the setting of coronary angioplasty. Pre-angioplasty (N = 14) and post-angioplasty (N = 19) measurements of coronary flow reserve were obtained by digital subtraction cineangiography in the myocardial region supplied by the dilated coronary artery, and with the Doppler probe in the proximal part of the dilated vessel. The reactive hyperaemia following the final balloon inflation was recorded with the Doppler balloon catheter still positioned across the stenotic lesion. Coronary stenosis geometry was quantified with the Cardiovascular Angiography Analysis System. When the epicardial stenosis was the only factor causing a reduction in coronary flow reserve, flow reserve measured with both digital subtraction cineangiography and with the Doppler probe correlated well with the cross-sectional area at the site of obstruction, r = 0.88, SEE = 0.36 and r = 0.77, SEE = 0.45 respectively. In contrast, when other factors decreasing coronary flow reserve were present (intimal dissection, left ventricular hypertrophy, previous myocardial infarction, collaterals) measurements obtained with both techniques correlated poorly with cross-sectional area (r = 0.55, SEE = 0.57, and r = 0.59, SEE = 0.50). Flow reserve measurements obtained with digital subtraction cineangiography correlated well with the measurements obtained with the Doppler probe (r = 0.85, SEE = 0.38, and r = 0.87, SEE = 0.34), although the two approaches have methodologically nothing in common and their respective regions of interest (myocardium for the radiographic technique and intracoronary lumen for the Doppler technique) are basically different. Furthermore, the reactive hyperaemia following the final balloon inflation was related to the flow reserve measured with both the angiographic technique (r = 0.85, SEE = 0.34) and the Doppler technique (r = 0.83, SEE = 0.32) using pharmacologically induced coronary vasodilation with intracoronary papaverine. This suggests that the same quantity of coronary flow reserve that can be recruited pharmacologically can be recruited by ischaemia following a transluminal occlusion.

Fracture of a balloon on a wire device during coronary angioplasty

In a 61-year-old patient with unstable angina an attempt was made to dilate a severe stenosis in a tortuous obtuse marginal branch. The initial attempt with conventional equipment was not successful; although the wire could be advanced distal to the stenosis, a 2.0 balloon did not cross the stenosis. A second attempt with a balloon on a wire device resulted in fracture of this catheter, with the distal 2.8-cm-long fragment looped in the left coronary artery. Immediate bypass surgery was performed and the broken fragment was easily removed from the left coronary ostium. The patient made an uneventful recovery.

Indications for pacemaker implantation in the Kearns-Sayre syndrome

The Kearns-Sayre syndrome is a rare condition, characterized by progressive external ophthalmoplegia, retinal pigmentary degeneration and progressive impairment of cardiac conduction, which mainly determines the prognosis. Two young patients (aged 13 and 18 years) without symptoms of cardiac disease presented with an electrocardiogram showing sinus rhythm, a normal atrio-ventricular conduction time, right bundle branch block and a left anterior fascicular block. Electrophysiologic investigation showed prolongation of His-ventricular interval at rest, which further increased during atrial pacing. Because of the potential progression of the conduction abnormalities and threatening sudden death, we decided to implant a pacemaker in both patients. Ten months later one patient had become pacemaker-dependent. Prophylactic pacemaker therapy is advisable in patients suffering from the Kearns-Sayre syndrome, who have bifascicular block on the precordial electrocardiogram.

Which cineangiographically assessed anatomic variable correlates best with functional measurements of stenosis severity? A comparison of quantitative analysis of the coronary cineangiogram with measured coronary flow reserve and exercise/redistribution thallium-201 scintigraphy

The goal of this investigation was to establish which measured anatomic variable of stenotic coronary lesions correlates best with functional severity. Therefore, 38 patients with single vessel disease underwent coronary cineangiography and exercise/redistribution thallium-201 scintigraphy. The computer-based Cardiovascular Angiography Analysis System was used to determine the cross-sectional area at the site of obstruction (OA) and percent diameter stenosis (DS), and to calculate the pressure drop over the stenosis (PD) with use of fluid dynamic equations. Coronary flow reserve was measured radiographically. Myocardial perfusion defects on thallium scintigrams were analyzed quantitatively and by visual interpretation. The relations between coronary flow reserve (CFR) and the three anatomic variables were described by the following equations: 1) CFR = 4.6 - 0.053 DS, r = 0.82; SEE: 0.79, p less than 0.001. 2) CFR = 0.5 + 0.75 OA, r = 0.87; SEE: 0.68, p less than 0.001). 3 CFR = 3.6 - 1.5 log PD, r = 0.90; SEE: 0.62, p less than 0.001. The calculated pressure drop was highly predictive of the thallium scintigraphic results with a sensitivity of 94% and a specificity of 90%. The calculated pressure drop is a better anatomic variable for assessing the functional importance of a stenosis than is percent diameter stenosis or obstruction area. However, the 95% confidence limits of the relation between pressure drop and coronary flow reserve are wide, making the measurement of coronary flow reserve an indispensable addition to quantitative angiography, especially when determining the functional importance of moderately severe coronary artery lesions.

Assessment of immediate and long-term functional results of percutaneous transluminal coronary angioplasty

Assessment of the functional significance of coronary artery lesions during cardiac catheterization has recently become possible by calculating coronary flow reserve from both myocardial contrast appearance time and density in the resting and hyperemic states determined from digitized coronary cineangiograms. However, the interobserver and intraobserver variabilities, as well as the short-, medium-, and long-term variabilities of the coronary flow reserve measurements, have to be established before this technique becomes an acceptable means of assessing the immediate and long-term functional results of revascularization procedures such as percutaneous transluminal coronary angioplasty (PTCA). Variability was defined as the mean difference and standard deviation of the difference between duplicate determinations of coronary flow reserve. The intraobserver variability (mean difference +/- SD) in the measurement of coronary flow reserve was -0.01 +/- 0.07. Interobserver variability by two observers was +0.08 +/- 0.52. Short-term variability based on the analysis of two coronary cineangiograms taken 5 minutes apart was -0.02 +/- 0.26. Medium-term variability (coronary cineangiographies repeated 1-3 hours apart) was found to be -0.06 +/- 0.52. Long-term variability (coronary cineangiographies repeated 3-5 months apart) was 0.11 +/- 0.63. Having established the reproducibility of this radiographic method, we studied the prospective changes in coronary flow reserve in 25 patients undergoing PTCA for single vessel coronary artery disease. Coronary flow reserve measurements and quantitative coronary cineangiography were performed before, immediately after, and 3-5 months after PTCA. PTCA resulted in an immediate increase in coronary flow reserve from 1 +/- 0.3 to 2.3 +/- 0.6 with a concomitant increase in obstruction area from 0.9 +/- 0.3 to 3.3 +/- 0.7 mm2. Nine of the 25 patients developed restenosis defined as a diameter stenosis greater than 50% at follow-up. The other 16 patients had a coronary flow reserve of 3.3 +/- 0.6, which was measured 3-5 months after PTCA. Coronary flow reserve measurement from digitized coronary cineangiograms is a reproducible method for the assessment of the physiological importance of coronary artery obstructions. Short-, medium-, and long-term investigations of the functional results of interventions such as pharmacological therapy or revascularization can be performed reliably with this technique.

Three-dimensional reconstruction of myocardial contrast perfusion from biplane cineangiograms by means of linear programming techniques

The assessment of coronary flow reserve from the instantaneous distribution of the contrast agent within the coronary vessels and myocardial muscle at the control state and at maximal flow has been limited by the superimposition of myocardial regions of interest in the two-dimensional images. To overcome these limitations, we are in the process of developing a three-dimensional (3D) reconstruction technique to compute the contrast distribution in cross sections of the myocardial muscle from two orthogonal cineangiograms. To limit the number of feasible solutions in the 3D-reconstruction space, the 3D-geometry of the endo- and epicardial boundaries of the myocardium must be determined. For the geometric reconstruction of the epicardium, the centerlines of the left coronary arterial tree are manually or automatically traced in the biplane views. Next, the bifurcations are detected automatically and matched in these two views, allowing a 3D-representation of the coronary tree. Finally, the circumference of the left ventricular myocardium in a selected cross section can be computed from the intersection points of this cross section with the 3D coronary tree using B-splines. For the geometric reconstruction of the left ventricular cavity, we envision to apply the elliptical approximation technique using the LV boundaries defined in the two orthogonal views, or by applying more complex 3D-reconstruction techniques including densitometry. The actual 3D-reconstruction of the contrast distribution in the myocardium is based on a linear programming technique (Transportation model) using cost coefficient matrices. Such a cost coefficient matrix must contain a maximum amount of a priori information, provided by a computer generated model and updated with actual data from the angiographic views. We have only begun to solve this complex problem. However, based on our first experimental results we expect that the linear programming approach with advanced cost coefficient matrices and computed model will lead to acceptable solutions in the 3D-reconstruction of the myocardial contrast distribution from biplane cineangiograms.

Correlations between quantitative cineangiography, coronary flow reserve measured with digital subtraction cineangiography and exercise thallium perfusion scintigraphy

The goal of this investigation was to establish which anatomical parameters of stenotic lesions correlate best with its functional severity. Therefore, thirty-eight patients with single vessel disease underwent coronary cineangiography and exercise/redistribution thallium-201 scintigraphy. Cross-sectional area at the site of obstruction (OA), percentage diameter stenosis (DS), the calculated pressuredrop over the stenosis (PD), as well as coronary flow reserve (CFR) derived from myocardial contrast appearance time and density were determined. The relations between CFR and the 3 anatomical parameters were described by the following equations: CFR = 4.6 - 0.053 DS, r = 0.82, SEE: 0.79, p less than 0.001 CFR = 0.5 + 0.75 OA, r = 0.87, SEE: 0.68, p less than 0.001 CFR = 3.6 - 1.5 log PD, r = 0.90, SEE: 0.62, p less than 0.001 The calculated pressuredrop was highly predictive of the thallium scintigraphic results with a sensitivity of 94% and a specificity of 90%. Therefore, the calculated pressuredrop is a better anatomical parameter for assessing the functional importance of a stenosis than percentage diameter stenosis or obstruction area. However, the 95% confidence limits of the relation between pressuredrop and coronary flow reserve are wide, making measurement of CFR a valuable addition to quantitative angiography, especially when determining the functional importance of moderately severe coronary artery lesions.

Coronary angioplasty for unstable angina

The clinical syndrome of unstable angina causes great concern to clinicians because of the high risk of progression to myocardial infarction or cardiac death. Management of unstable angina pectoris has evolved progressively, and recently coronary angioplasty has been shown to be a relatively safe and effective treatment of unstable angina. The aim of this study was to report our experience with the immediate and one year follow-up results of percutaneous transluminal coronary angioplasty (PTCA) in patients with unstable angina. Unstable angina was defined as prolonged periods of chest pain at rest, associated with ST-T changes and no subsequent myocardial necrosis. All patients were treated with a combination of nitroglycerin, beta-blockers or calcium antagonists. The patients were classified into three clinically relevant subgroups. Group I: unstable angina stabilized with pharmacological treatment but with persistent exertional angina (71 patients): group II: unstable angina refractory to optimal pharmacological treatment (88 patients) and group III: recurrent unstable angina within 30 days of myocardial infarction (53 patients). The initial success rate was 87 p. 100 for group I, 92 p. 100 for group II and 89 p. 100 for group III and the major complication rates were 13 p. 100, 8 p. 100 and 11 p. 100 respectively. At 1 year follow-up after initial successful PTCA late death had occurred in 2 p. 100 in group I, 1 p. 100 in group II and 0 p. 100 in group III and a late nonfatal infarction in 2 p. 100, 1 p. 100 and 4 p. 100 respectively. The frequency of recurrent angina was 23 p. 100 in group I, 20 p. 100 in group II and 26 p. 100 in group III. Thus, coronary angioplasty for unstable angina can be performed with a high initial success rate, but at an increased risk on major complications. The prognosis after an initial successful coronary angioplasty is favourable.

Percutaneous transluminal coronary angioplasty for angina pectoris after a non-Q-wave acute myocardial infarction

Despite initially favorable prognosis in patients with non-Q-wave acute myocardial infarction (AMI), long-term mortality in this subset of patients appears to be similar to or even greater than that in patients with Q-wave AMI. The relatively poor late prognosis is primarily due to a high incidence of unstable angina and recurrent AMI. Between January 1982 and January 1987, 114 patients with suitable coronary narrowing underwent percutaneous transluminal coronary angioplasty (PTCA) for angina pectoris (present either at rest or during mild exertion, and despite optimal pharmacologic therapy), a median of 31 (range 2 to 362) days after a non-Q-wave AMI. Success was achieved in dilating the obstructed artery in 98 patients (113 of the 129 dilated arteries). Emergency bypass surgery was performed in 7 patients. Mean clinical follow-up of 20 (range 3 to 59) months was obtained in all patients and revealed no deaths. Of the 98 patients with successful PTCAs, 6 (6%) developed a nonfatal recurrent AMI and 62 (63%) were asymptomatic. However, recurrent angina affected 31 patients (32%) and was treated by repeat PTCA (n = 18), coronary bypass surgery (n = 5) or pharmacologic therapy (n = 8). At follow-up, 74% of the patients (73 of 98) were asymptomatic after a successful PTCA and, if necessary, a repeat PTCA, without incidence of recurrent AMI, coronary bypass surgery or death. The high initial success rate, low incidence of subsequent death and late recurrent AMI and sustained symptomatic benefit suggest that PTCA is an effective initial treatment strategy in these selected patients.

Coronary blood flow velocity during percutaneous transluminal coronary angioplasty as a guide for assessment of the functional result

To investigate the clinical usefulness of intracoronary Doppler recordings during percutaneous transluminal coronary angioplasty (PTCA), the changes of intracoronary blood flow velocity during PTCA were assessed in 20 patients with single proximal coronary stenosis, using a Doppler probe end-mounted on the tip of a PTCA catheter. A mean of 4 inflations was performed in each patient. Intracoronary velocities were measured before and after each inflation and during peak reactive hyperemia after each transluminal occlusion. Quantitative analysis of the coronary stenosis was assessed before and after PTCA, and the dilatation resulted in an increase in minimal luminal cross-sectional area from 1.1 +/- 0.8 to 2.7 +/- 1.2 mm2. A gradual and significant improvement in velocities was observed after the first 3 dilatations, but in 15 of the 20 patients the resting and hyperemic velocities were not affected by the fourth dilatation. Coronary flow reserve measured during reactive hyperemia after the last dilatation with the PTCA catheter across the lesion was 1.9. This value of coronary flow reserve is compatible with the residual stenosis measured after PTCA when corrected for the presence of the Doppler balloon catheter (0.68 mm2). This application of the Doppler technique may provide a new method of on-line functional monitoring of the PTCA procedure in individual patients, but does not yet allow an accurate prediction of the change in coronary geometry brought about by PTCA.

Does intracoronary papaverine dilate epicardial coronary arteries? Implications for the assessment of coronary flow reserve

Intracoronary papaverine is used as a means to induce a strong and short-lasting hyperemia in several recently developed methods to measure coronary flow reserve. Changes in stenosis geometry from papaverine would influence the measured coronary flow reserve. Therefore, we investigated the influence of intracoronary papaverine on stenosis geometry with quantitative analysis of the coronary angiogram and assessed the influence of papaverine on pressure-flow characteristics of the stenosis and coronary flow reserve. The cross-sectional areas (mean +/- SD) of the stenosis increased 18% +/- 7% after papaverine. The normal proximal and distal parts of the coronary artery dilated 5% +/- 2% after papaverine. This results in a decrease of the calculated pressure drop over the stenosis varying from 20% to 30%. Coronary flow reserve of a flow-limiting epicardial stenosis is overestimated by 16% when papaverine is used to induce hyperemia. These papaverine-induced changes can nevertheless be circumvented by maximal vasodilation of the major epicardial coronary artery with 3 mg intracoronary isosorbidedinitrate prior to the investigation of the coronary flow reserve with papaverine.

Value and limitations of intracoronary adenosine for the assessment of coronary flow reserve

An ideal coronary vasodilator for studying coronary flow reserve should rapidly produce a maximal hyperemic response, be short acting to permit repeated measurements, and not alter systemic hemodynamics. We measured with a Doppler tip balloon catheter, in 12 patients before and/or after percutaneous transluminal coronary angioplasty the hyperemic response following 12.5 mg intracoronary papaverine and following gradually incremental bolus injections of intracoronary adenosine, starting from 0.05 mg until a maximal hyperemic response or side effects. The mean dose (+/- SD) of adenosine needed to produce maximal hyperemia was 0.23 (+/- 0.20 mg). Coronary blood flow velocity after adenosine increased to 1.6 +/- 0.3 times resting coronary blood flow velocity, comparable in magnitude to the hyperemia following intracoronary papaverine. The time from injection to peak effect after adenosine was 7.4 (SD +/- 2.2) sec and after papaverine 26 (SD +/- 7) sec. Adenosine resulted in a bradyarrhythmia in three patients. Intracoronary adenosine is a potent and very short acting vasodilator for studying coronary flow reserve, but the side effects and unpredictability of the dosage needed to produce maximal hyperemia may limit its applicability.

Normalization of coronary flow reserve by percutaneous transluminal coronary angioplasty

Fifteen patients undergoing routine follow-up angiography 5 months after successful percutaneous transluminal coronary angioplasty (PTCA) without angina and with normal exercise thallium scintigraphy were selected for analysis. The coronary flow reserves of these patients were compared with those of 24 patients with angiographically normal coronary arteries to establish whether PTCA can restore to normal the coronary flow reserve of patients with chronic coronary artery disease. The quantitative cineangiographic changes and the concomitant alterations in coronary flow reserve as an immediate result of the PTCA and the subsequent changes 5 months later are described. Coronary flow reserve was measured with digital subtraction cineangiography. PTCA resulted in an increase in minimal obstruction area (mean +/- standard deviation) from 0.8 +/- 0.3 to 3.4 +/- 0.7 mm2 and in coronary flow reserve from 1.0 +/- 0.3 to 2.5 +/- 0.6. Five months later a further substantial and significant (p less than 0.05) late increase in obstruction area (3.8 +/- 0.9 mm2) and flow reserve (3.6 +/- 0.5) had occurred. In 11 of 15 patients coronary flow reserve was restored to normal. Changes in stenosis geometry are likely to be 1 of the major determinants of this late normalization of coronary flow reserve.

[Intracoronary blood flow velocity during angioplasty. Functional guide and indicator of the success of dilatation]

In order to assess the value of a new Doppler-fitted dilatation catheter, changes in blood flow velocities in the coronary arteries were recorded at various stages of transluminal angioplasty in 15 patients with isolated proximal coronary stenosis. A pulsed Doppler probe (emission frequency 20 MHz, recurrence frequency 62.5 MHz) attached to the distal end of the balloon catheter was used to measure blood flow velocities with a Doppler frequency/velocity relationship of about 3.75 cm/s per KHz. During each angioplasty the balloon was inflated 4 times on average, with successive increases of pressure from 7 to 12 atmospheres. Flow velocities were measured before and after each inflation and also when maximum hyperaemia occurred after temporary occlusion by the inflated balloon. Computer-assisted analysis of the coronary stenosis was carried out before and after the procedure. Patient's mean age was 53 years. Angioplasty was performed in the anterior interventricular artery (12 cases), the circumflex artery (2 cases) or the right coronary artery (1 case). Anatomical success was assessed by an increase of minimum luminal section area from 1.3 +/- 0.0 to 3.0 +/- 1.2 mm2. Functional success was assessed by a progressive and significant increase of the velocities measured during the first 3 dilatations. No further increase of velocity was observed between the last 2 inflations. Coronary reserve at the end of angioplasty was 2.1, corresponding to the theoretical value calculated taking into account the residual stenosis and the presence of the catheter in situ.(ABSTRACT TRUNCATED AT 250 WORDS)