Comparative long-term effects of coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty on regional coronary flow reserve.

peer reviewedTo evaluate the relative long-term improvement in coronary artery hemodynamics after revascularization by coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA), regional coronary flow reserve (CFR) was measured, by digital computer analysis of 35 mm cine film, in 50 men undergoing cardiac catheterization. CFR (mean +/- SEM) in 12 atherosclerotic arteries before revascularization was 1.02 +/- 0.05. Mean CFR in 29 normal arteries of men with normal coronary arteriograms was significantly higher (2.59 +/- 0.11) than that in 16 atherosclerotic arteries of patients revascularized by CABG (2.02 +/- 0.17, p less than .01) or in 14 atherosclerotic arteries of those revascularized by PTCA (1.97 +/- 0.12, p less than .01). No difference in CFR between the CABG and PTCA groups was found and variables known to influence CFR were similar between groups. Equivalent and significant long-term improvement in coronary artery hemodynamics is provided by CABG or PTCA. We postulate that the difference in CFR in the men with normal arteries and those who underwent revascularization was related to the effects of the general atherosclerotic process, which remain despite successful treatment by these techniques

Quantitative assessment of global and regional left ventricular function with low-contrast dose digital subtraction ventriculography.

Few studies have compared the use of low-contrast dose digital subtraction ventriculography with conventional ventriculography for quantitative assessment of both global and regional left ventricular function. Accordingly, 34 patients underwent conventional ventriculography using 36 ml of ionic contrast material and digital ventriculography (mask-mode) using 10 ml of contrast diluted in 10 ml of saline and injected over two seconds. Data from two patients were excluded because of ectopy during cineventriculography and from one because of ectopy during both studies. End-diastolic and end-systolic volumes were calculated from both studies by an area-length method and used to calculate ejection fractions. Regional wall motion was quantitated by the centerline method. Results of linear regression analysis demonstrated high correlations for all parameters (end-diastolic volume, r = 0.85; end-systolic volume, r = 0.93; ejection fraction, r = 0.92; quantitative regional wall motion, r = 0.90). Thus, low-contrast dose digital subtraction ventriculography provides an accurate assessment of both global and regional ventricular function and minimizes the required dose and inherent risks of contrast media

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 for 11 arteries undergoing a successful procedure. Exercise thallium-201 (Tl-201) and radionuclide ventriculography (RNV) were performed within 3 days before and after PTCA and compared to % diameter stenosis, % translesional gradient and regional coronary flow reserve (CFR) determined by digital coronary angiography. Primary success of the procedure was gauged by reduction in % stenosis from 80 +/- 12% to 31 +/- 12% (residual stenosis less than 50% in all cases) and reduction in % gradient less than 25% in all cases). Before PTCA, Tl-201 and/or RNV were abnormal in all cases. After PTCA, radionuclide exercise tests improved but remained abnormal in 4 instances. No relationship was found between residual % gradient or stenosis and pathological Tl-201 or RNV following PTCA, but abnormal tests were observed among 4 out of the 5 vessels with the lowest CFR (less than 1.69). In one case CFR remained depressed despite good angiographic, hemodynamic and scintigraphic results, this patient had unstable angina before the procedure. Among patients with stable symptoms, CFR of arterial distributions with positive Tl-201 or RNV after PTCA was significantly lower than that with negative tests (1.58 +/- 0.05 as compared to 1.90 +/- 0.25, P less than 0.02). Early radionuclide stress tests results thus reflect the physiologic improvement of coronary circulation. They may reflect the persistence of coronary flow abnormalities despite the relief of the epicardial stenosis

Abnormal coronary flow reserve and abnormal radionuclide exercise test results in patients with normal coronary angiograms.

Coronary flow reserve, exercise thallium-201 scintigraphy and exercise radionuclide ventriculography were compared in 18 patients with chest pain and angiographically normal coronary arteries. Regional exercise thallium-201 perfusion was abnormal in three patients, regional exercise wall motion was abnormal in three other patients and results of both tests were abnormal in one additional patient. Left ventricular ejection fraction responses were abnormal in five of these seven patients. The coronary flow reserve of arterial distributions with abnormal perfusion or regional dysfunction was significantly lower than that of distributions associated with normal radionuclide results (1.42 +/- 0.23 versus 2.58 +/- 0.83, p less than 0.001). All patients with abnormal scintigraphic results had low coronary flow reserve (less than 1.95) in at least one distribution. Perfusion abnormalities appeared to be more localized in the arterial distributions with the lowest flow reserve. Only two patients had low flow reserve (less than 1.95) with normal scintigraphic results; both were hypertensive. These data suggest that abnormal exercise scintigraphic findings in patients with angiographically normal coronary arteries and chest pain are indicative of true blood flow or perfusion abnormalities

Validation in dogs of a rapid digital angiographic technique to measure relative coronary blood flow during routine cardiac catheterization.

peer reviewedAssessment of the functional significance of anatomically defined coronary stenoses has been hampered by the lack of clinically applicable techniques of measuring coronary blood flow or flow ratios. A digital angiographic technique is reported that allows rapid analysis of relative regional coronary blood flow during routine cardiac catheterization. This technique was validated in dogs by comparing digital flow ratio estimates with electromagnetic-flow (EMF) ratio measurements. Fourteen open-chest dogs had EMF probes placed on the proximal left anterior descending artery before selective coronary angiography. Electrocardiographically gated images were acquired directly by a digital radiographic system during both baseline blood flow and either contrast or papaverine-induced hyperemia. Dual-parameter functional images were generated using color and intensity coding to represent contrast arrival time and contrast density, respectively. For analysis, myocardial areas of interest were created over the distal perfusion bed of the left anterior descending coronary artery. Mean contrast density/appearance time (CD/AT) values were computer calculated as the mean density divided by the mean arrival time for each. Coronary flow reserve was determined as the ratio of the CD/AT value for a hyperemic image divided by the CD/AT value for the corresponding baseline image. CD/AT ratios correlated well (r = 0.92) with actual EMF ratios (CD/AT Ratio = 0.90 EMF Ratio +0.12, n = 48 ratios). Reproducibility was +/- 13%. Interobserver (r = 0.99) and intraobserver (r = 0.98) variability was excellent. Thus, rapid, accurate and reproducible estimates of relative regional coronary blood flow are possible using digital radiography