Coronary artery flow velocity is related to lumen area and regional left ventricular mass.

BACKGROUND: Coronary flow velocity varies widely between individuals, even at rest. Because of this variation, indices with less apparent deviation, such as the ratio of hyperemic to resting velocity (coronary flow reserve), have been more commonly studied. We tested the hypothesis that the flow continuity principle could be used to model resting coronary flow, and we examined the resulting velocity relationship. METHODS AND RESULTS: We studied coronary velocity in 59 patients using a Doppler wire to measure resting and hyperemic average peak velocities in the left anterior descending artery. Quantitative techniques were used to calculate lumen cross-sectional area and the lengths of all distal coronary branches. Branch lengths were used to estimate regional left ventricular mass. We then calculated the ratio of lumen area to regional mass (A/m). Regional perfusion was estimated from the double product of heart rate and systolic blood pressure. Resting velocity (V) varied inversely with A/m ratio [V=46.5/(A/m); r=0.68, P<0.001]. Disease in the left anterior descending artery was categorized as none or luminal irregularities only (n=22), mild (n=15), or moderate (n=22). The A/m ratio declined across these groups (8.7+/-4.0, 8.5+/-6.2, and 5. 6+/-3.0 mm(2)/100 g, respectively; P<0.04), and the resting average peak velocity increased (27+/-16, 33+/-11, and 37+/-20 cm/s, respectively; P=0.06). CONCLUSIONS: Resting coronary artery flow velocity is inversely related to the ratio of lumen area to regional left ventricular mass. Higher resting velocities are found when insufficient lumen size exists for the distal myocardial bed, as occurs with diffuse mild or moderate coronary atherosclerosis.

Intensive lifestyle changes for reversal of coronary heart disease.

CONTEXT: The Lifestyle Heart Trial demonstrated that intensive lifestyle changes may lead to regression of coronary atherosclerosis after 1 year. OBJECTIVES: To determine the feasibility of patients to sustain intensive lifestyle changes for a total of 5 years and the effects of these lifestyle changes (without lipid-lowering drugs) on coronary heart disease. DESIGN: Randomized controlled trial conducted from 1986 to 1992 using a randomized invitational design. PATIENTS: Forty-eight patients with moderate to severe coronary heart disease were randomized to an intensive lifestyle change group or to a usual-care control group, and 35 completed the 5-year follow-up quantitative coronary arteriography. SETTING: Two tertiary care university medical centers. INTERVENTION: Intensive lifestyle changes (10% fat whole foods vegetarian diet, aerobic exercise, stress management training, smoking cessation, group psychosocial support) for 5 years. MAIN OUTCOME MEASURES: Adherence to intensive lifestyle changes, changes in coronary artery percent diameter stenosis, and cardiac events. RESULTS: Experimental group patients (20 [71%] of 28 patients completed 5-year follow-up) made and maintained comprehensive lifestyle changes for 5 years, whereas control group patients (15 [75%] of 20 patients completed 5-year follow-up) made more moderate changes. In the experimental group, the average percent diameter stenosis at baseline decreased 1.75 absolute percentage points after 1 year (a 4.5% relative improvement) and by 3.1 absolute percentage points after 5 years (a 7.9% relative improvement). In contrast, the average percent diameter stenosis in the control group increased by 2.3 percentage points after 1 year (a 5.4% relative worsening) and by 11.8 percentage points after 5 years (a 27.7% relative worsening) (P=.001 between groups. Twenty-five cardiac events occurred in 28 experimental group patients vs 45 events in 20 control group patients during the 5-year follow-up (risk ratio for any event for the control group, 2.47 [95% confidence interval, 1.48-4.20]). CONCLUSIONS: More regression of coronary atherosclerosis occurred after 5 years than after 1 year in the experimental group. In contrast, in the control group, coronary atherosclerosis continued to progress and more than twice as many cardiac events occurred.

Estrogen replacement therapy and outcome of coronary balloon angioplasty in postmenopausal women.

Estrogen replacement therapy (ERT) in women after menopause is associated with prevention of clinical coronary artery disease. However, few studies have investigated possible benefits from ERT in postmenopausal women undergoing treatment for established coronary disease. We therefore retrospectively reviewed the clinical outcomes of 428 postmenopausal women undergoing percutaneous transluminal coronary balloon angioplasty (PTCA) to test the hypothesis that ERT has a beneficial effect in this setting. The women were divided into 2 groups based on ERT status at the time of the procedure. Estrogen users were younger (60 +/- 10 vs 68 +/- 9 years, p <0.001), more commonly had family histories of coronary heart disease (54% vs 41%, p = 0.04), had less incidence of hypertension (63% vs 76%, p = 0.02), and had slightly fewer diseased vessels per patient (1.3 +/- 0.5 vs 1.5 +/- 0.7, p = 0.03) compared with nonusers. No in-hospital deaths occurred in estrogen users compared with 5% hospital mortality in nonusers (p = 0.01). The combined outcome of death or myocardial infarction (MI) also was lower in estrogen users (4% vs 12%, p = 0.04). Of 348 women discharged after successful PTCA, 336 (97%) were able to be contacted at an average follow-up interval of 22 +/- 17 months (range 5 to 82). Estrogen users had superior event-free survival both for death as well as for death or nonfatal MI. Repeat revascularizations were similar in both groups (32% vs 24%, p = 0.15). In a Cox proportional-hazards model, nonusers had 4 times the likelihood of death after angioplasty compared with estrogen users (OR = 4.025, 95% CI = 1.3 to 13.4, p = 0.02). We conclude that estrogen replacement may offer protection against clinical coronary events in postmenopausal women who already have established coronary disease and are undergoing balloon angioplasty. The benefit was independent of age, smoking, presence of diabetes mellitus, or the number of diseased coronary vessels. However, it did not include a reduction in repeat revascularization procedures, suggesting no reduction in restenosis.

Comparison of angioscopy, intravascular ultrasound imaging and quantitative coronary angiography in predicting clinical outcome after coronary intervention in high risk patients.

OBJECTIVES: The purpose of this study was to identify qualitative or quantitative variables present on angioscopy, intravascular ultrasound imaging or quantitative coronary arteriography that were associated with adverse clinical outcome after coronary intervention in high risk patients. BACKGROUND: Patients with acute coronary syndromes and complex lesion morphology on angiography are at increased risk for acute complications after coronary angioplasty. Newer devices that primarily remove atheroma have not improved outcome over that of balloon angioplasty. Intravascular imaging can accurately identify intraluminal and intramural histopathologic features not adequately visualized during coronary arteriography and may provide mechanistic insight into the pathogenesis of abrupt closure and restenosis. METHODS: Sixty high risk patients with unstable coronary syndromes and complex lesions on angiography underwent angioscopy (n = 40) and intravascular ultrasound imaging (n = 46) during interventional procedures. In 26 patients, both angioscopy and intravascular ultrasound were performed in the same lesion. All patients underwent off-line quantitative coronary arteriography. Coronary interventions included balloon (n = 21) and excimer laser (n = 4) angioplasty, directional (n = 19) and rotational (n = 6) atherectomy and stent implantation (n = 11). Patients were followed up for 1 year for objective evidence for recurrent ischemia. RESULTS: Patients whose clinical presentation included rest angina or acute myocardial infarction or who received thrombolytic therapy within 24 h of procedure were significantly more likely to experience recurrent ischemia after intervention. Plaque rupture or thrombus on preprocedure angioscopy or angioscopic thrombus after intervention were also significantly associated with adverse outcome. Qualitative or quantitative variables on angiography, intravascular ultrasound or off-line quantitative arteriography were not associated with recurrent ischemia on univariate analysis. Multivariate predictors of recurrent ischemia were plaque rupture on preprocedure angioscopy (p < 0.05, odds ratio [OR] 10.15) and angioscopic thrombus after intervention (p < 0.05, OR 7.26). CONCLUSIONS: Angioscopic plaque rupture and thrombus were independently associated with adverse outcome in patients with complex lesions after interventional procedures. These features were not identified by either angiography or intravascular ultrasound.

Rotational atherectomy with a new device: initial clinical experience.

The Bard Atherectomy Catheter is a new rotational atherectomy device that consists of a flexible, hollow, thin-walled cutting catheter that, while rotated at 1,500 revolutions per minute, is advanced across the lesion over a special spiral guidewire system. We report the initial clinical experience with this device in 20 peripheral lesions in ten patients. The majority of patients were treated for limb salvage. All lesions were successfully intervened on by atherectomy followed by adjunctive balloon angioplasty. A reduction to less than 50% stenosis was achieved in 13 of the 20 lesions (65%) after atherectomy but in all 20 lesions (100%) after adjunctive angioplasty for all lesions and stenting for dissections in two. Baseline minimal lesion lumen diameter was 0.8 +/- 0.7 mm with a reference vessel diameter of 4.2 +/- 1.7 mm (75 +/- 21% stenosis). The lumen improved to 2.0 +/- 0.8 mm (45 +/- 19% stenosis) (P < 0.001) following atherectomy and to 3.9 +/- 1.9 mm (13 +/- 16% stenosis) (P < 0.001) after adjunctive angioplasty. The average weight of removed atheroma was 45 +/- 58 mg. All ten patients had initial improvement in symptoms. At 6 months follow-up there was persistent improvement in eight patients and two subjects had undergone amputations. Our early clinical experience with this low profile, flexible atherectomy device, that enables extraction of a large amount of atheroma, suggests that it will become a valuable addition to current atherectomy technologies in small- and medium-sized vessels. The value of this device in coronary vessels is under investigation.

Coronary artery flow monitoring: the value of intravascular Doppler for detection of complications after interventions.

Ultrasound transducer-tipped guidewires can be used for coronary interventions, and they permit the monitoring of coronary flow before, during, and after the interventions. The flow signal contains valuable information regarding the quality and stability of the final result. Restoration of typical phasic flow patterns with diastolic predominance is one guide to final result. Monitoring the trend in average velocity over several minutes after completion of the procedure can detect subtle alterations in flow that may presage abrupt closure. These flow alterations might also help predict active plaques with heavy thrombus involvement that may undergo recurrence in the weeks and months after successful procedures.

Coronary artery flow monitoring following coronary interventions.

Coronary guidewires with ultrasound transducer tips are commercially available and are appropriately sized for use in coronary interventions. These guidewires permit monitoring of coronary flow before, during and after the interventions. The measured flow signal contains valuable information regarding the quality and the stability of the final result. After completion of the procedure, monitoring the trend in average velocity over several minutes can reveal subtle alterations in flow that may presage abrupt closure. Abnormal or unstable flow patterns also may help predict lesions that might develop recurrences in the weeks and months after successful procedures.

Changes in proximal and distal coronary artery diameter during atrial pacing-induced myocardial ischemia.

BACKGROUND: The present study was designed to evaluate the role of tachycardia-induced dynamic coronary artery diameter changes in the development of myocardial ischemia. METHODS: Coronary angiography at rest and during atrial pacing-induced myocardial ischemia was performed in 22 patients. The diameter of the proximal and the corresponding distal coronary artery segments at rest and during pacing was measured using quantitative coronary angiography. Plasma levels of noradrenaline, adrenaline, dopamine and endothelin were determined in a subset of 14 patients in blood drawn from aorta and coronary sinus at rest and during pacing. RESULTS: Luminal diameter in normal proximal and distal segments increased, respectively, from 2.93 +/- 0.34 and 1.40 +/- 0.04 mm at rest to 3.03 +/- 0.25 and 1.58 +/- 0.07 mm during atrial pacing. The diameter of the proximal coronary artery segments with significant concentric stenosis decreased from 1.28 +/- 0.4 mm at rest to 0.95 +/- 0.34 mm during pacing, whereas segments with either significant eccentric or non-significant stenosis did not change significantly. A correlation was found between the noradrenaline level in the coronary sinus and the distal coronary artery diameter. CONCLUSIONS: A decrease in diameter of coronary artery segments with concentric stenosis during tachycardia might contribute to the development of myocardial ischemia. Some of the dynamic coronary artery changes may be influenced by the plasma level of noradrenaline. No evidence was found to suggest that dynamic changes in the diameter of proximal segments are related to the changes in diameter of the corresponding distal segments.

Analytic isocenter calibration. A new approach for accurate x-ray gantries.

Isocenter calibration transforms cardiac structures in digitized biplane angiograms to absolute dimensions, calculating their radiological magnification and video transformation. Since a scaling device is not required, isocenter calibration yields to more accurate measurements than the widely used reference object calibration. Both isocenter methods reported so far, regarding geometrically inaccurate x-ray gantries, yield to different and complex computational formulas. Since these formulas are hard to understand, isocenter calibration is less widely used. To facilitate the implementation of the isocenter calibration, the basic formulas for accurate x-ray gantries are derived. Shifting virtually one x-ray system onto the other, basic isocenter calibration is derived geometrically in three simple steps. The radiological magnification of an object is illustrated as a ratio of planes. The calculation of all parameters entering the computations is demonstrated geometrically, by use of the isocenter of the x-ray gantry. The derivation gives a clear idea of isocenter calibration. It is simple to derive and facilitates the understanding of the error regarding developments. When geometrical inaccuracies vanish, all formulas become equivalent. However, even if the inaccuracies increase, all methods provide nearly identical results, indicating the robustness of isocenter calibration.

Cyclic flow variations after coronary angioplasty in humans: clinical and angiographic characteristics and elimination with 7E3 monoclonal antiplatelet antibody.

OBJECTIVES: We tested the hypothesis that cyclic alterations in coronary artery blood flow that occurred after coronary angioplasty could be attenuated or abolished by a monoclonal antibody to the platelet surface membrane GP IIb/IIIa receptor. BACKGROUND: Coronary artery cyclic flow variations may occur after coronary angioplasty in experimental animal models and humans. In animal models of coronary thrombosis, cyclic alterations in flow often have preceded thrombotic occlusion or reocclusion. Several agents that inhibit platelet function have been shown to attenuate or eliminate cyclic flow variations in these models. METHODS: We monitored coronary artery flow in 27 patients for 30 min after coronary angioplasty, using 0.018-in. (0.046 cm) coronary guide wires with pulsed wave Doppler ultrasound transducers on the distal tips. Clinical data were collected and quantitative analyses performed on coronary arteriograms made before and after the angioplasty procedures. We compared findings in patients with and without cyclic flow variations detected. RESULTS: There were 20 men and 7 women. Mean age was 58 years, and 63% had unstable angina. They received standard doses of nitrates, aspirin, heparin, calcium channel antagonists and other medications clinically indicated. Nevertheless, we detected cyclic flow variations in five patients (19%). Four of these patients had stable flow restored with intravenous injection of 0.25 mg/kg normal body weight of monoclonal antibody c7E3 Fab to the platelet GP IIb/IIIa receptor. In one patient, stable flow was restored by repeat dilation when an immediate angiogram revealed renarrowing. Patients developing cyclic alterations in flow had longer lesions (18.7 +/- 7.5 mm vs. 13.1 +/- 5.7 mm, p < 0.05) that had responded less well to angioplasty (stenosis postangioplasty 47 +/- 13% vs. 33 +/- 15%, p < 0.05). CONCLUSIONS: Cyclic alterations in coronary artery blood flow may occur in some patients after coronary angioplasty, despite the use of standard antiplatelet, antithrombotic and antivasospastic medications. We found that they could be eliminated by this monoclonal antibody that blocks the final common event of platelet aggregation.

Restenosis revisited: insights provided by quantitative coronary angiography.

In this editorial, the problem of restenosis after coronary balloon angioplasty and other transluminal interventions is reviewed from the perspective of quantitative coronary angiography. The review is largely based on the experience of the Thoraxcentre in the application of quantitative angiography to the study of restenosis over the past decade, with incorporation and discussion of relevant and significant contributions from other groups. Current discrepancies in the angiographic definition of restenosis are highlighted and the use of percent diameter stenosis or MLD as the measurement parameter of choice is objectively addressed. Perspectives on the pathologic paradigm of restenosis are briefly reviewed as a basis from which to evaluate quantitative angiographic information provided by various studies. Particular attention is then paid, in chronologic fashion, to discussion and elaboration of insights to the restenosis process provided by quantitative angiographic studies, which have led to the introduction of some new methodological approaches to the comparison of short- and long-term angiographic luminal changes after various interventions. A word of caution on the potential pitfalls of quantitative angiographic studies is provided and counterbalanced with a discussion of clinical correlations of quantitative angiographic measurements. Finally, a proposal is made for the application of quantitative angiographic measurements to randomized clinical trials for the purpose of comparing new interventional devices.

Coronary artery flow monitoring following coronary interventions.

Technologic innovations have made it possible to measure coronary artery blood flow in awake patients. Both flow velocity as well as flow reserve can be assessed. In particular, the period of time immediately following coronary interventions offers a unique opportunity to study important features of coronary flow behavior. In 22 patients, coronary flow reserve was measured before and after an intervention, either angioplasty or atherectomy, using a 0.018-in Doppler guidewire (Flowire). The minimum lumen diameter (MLD) was increased from 1.0 +/- 0.4 to 1.7 +/- 0.4 mm, while coronary flow velocity increased significantly, rising from 29 +/- 13 to 39 +/- 14 cm/sec (p < 0.025). The maximum hyperemic velocity also increased, from 44 +/- 16 to 69 +/- 21 cm/sec. Using only the preintervention or postintervention values, the flow reserve ratio was 1.53 +/- 0.4 prior to intervention and 1.84 +/- 0.5 after intervention (p = nonsignificant). However, the post-intervention value may have been artifactually reduced by the fact that both resting as well as hyperemic velocities increased. When the post-intervention flow reserve ratio was recalculated, using the preintervention resting value, flow reserve ratio was seen in increase from 1.53 +/- 0.4 to 2.73 +/- 1.2 (p < 0.001). Measurements of coronary flow in the postintervention period also revealed several interesting phenomena. Spasm of a coronary artery was documented, and its resolution in response to intracoronary nitroglycerin was observed. Elastic recoil following angioplasty was documented by gradual decline in coronary flow over 30 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental basis of determining maximum coronary, myocardial, and collateral blood flow by pressure measurements for assessing functional stenosis severity before and after percutaneous transluminal coronary angioplasty.

BACKGROUND: Severity of coronary artery stenosis has been defined in terms of geometric dimensions, pressure gradient-flow relations, resistance to flow and coronary flow reserve, or maximum flow capacity after maximum arteriolar vasodilation. A direct relation between coronary pressure and flow, however, may only be presumed if the resistances in the coronary circulation are constant (and minimal) as theoretically is the case during maximum arteriolar vasodilation. In that case, pressure measurements theoretically can be used to predict maximum flow and assess functional stenosis severity. METHODS AND RESULTS: A theoretical model was developed for the different components of the coronary circulation, and a set of equations was derived by which the relative maximum flow or fractional flow reserve in both the stenotic epicardial artery and the myocardial vascular bed and the proportional contribution of coronary arterial and collateral flow to myocardial blood flow are calculated from measurements of arterial, distal coronary, and central venous pressures during maximum arteriolar vasodilation. To test this model, five dogs were acutely instrumented with an epicardial, coronary Doppler flow velocity transducer. Distal coronary pressures were measured by an ultrathin pressure-monitoring guide wire (0.015 in.) with minimal influence on transstenotic pressure gradient. Fractional flow reserve was calculated from the pressure measurements and compared with relative maximum coronary artery flow measured directly by the Doppler flowmeter at three different levels of arterial pressure for each of 12 different severities of stenosis at each pressure level. Relative maximum blood flow through the stenotic artery (Qs) measured directly by the Doppler flowmeter showed an excellent correlation with the pressure-derived values of Qs (r = 0.98 +/- 0.01, intercept = 0.02 +/- 0.03, slope = 0.98 +/- 0.04), of the relative maximum myocardial flow (r = 0.98 +/- 0.02, intercept = 0.26 +/- 0.07, slope = 0.73 +/- 0.08), and of the collateral blood flow (r = 0.96 +/- 0.04, intercept = 0.24 +/- 0.07, slope = -0.24 +/- 0.06). Moreover, the theoretically predicted constant relation between mean arterial pressure and coronary wedge pressure, both corrected for venous pressure, was confirmed experimentally (r = 0.97 +/- 0.03, intercept = 9.5 +/- 13.3, slope = 4.4 +/- 1.2). CONCLUSIONS: These results provide the experimental basis for determining relative maximum flow or fractional flow reserve of both the epicardial coronary artery and the myocardium, including collateral flow, from pressure measurements during maximum arteriolar vasodilation. With a suitable guide wire for reliably measuring distal coronary pressure clinically, this method may have potential applications during percutaneous transluminal coronary angioplasty for assessing changes in the functional severity of coronary artery stenoses and for estimating collateral flow achievable during occlusion of the coronary artery.

Measurement from arteriograms of regional myocardial bed size distal to any point in the coronary vascular tree for assessing anatomic area at risk.

OBJECTIVES: To obtain the size of regional myocardial mass for individual coronary arteries in vivo. BACKGROUND: The anatomic site of occlusion in a coronary artery does not predict the size of the risk area because location of the occlusion does not account for the size of the artery or of its dependent myocardial bed. METHODS: Intracoronary radiolabeled microspheres were injected and coronary arteriograms were quantitatively analyzed by semiautomated methods. The coronary artery lumen areas and the sum of epicardial coronary artery branch lengths distal to the points where radiomicrospheres had been injected were determined from both in vivo and postmortem coronary arteriograms. Regional myocardial mass distal to the point of each microsphere injection was correlated with corresponding distal summed coronary branch lengths and with coronary artery lumen areas. RESULTS: 1) Regional myocardial mass was closely and linearly related to sum of coronary artery branch lengths distal to any point in the coronary artery tree and therefore could be determined for any location on a coronary arteriogram. 2) The fraction of total left ventricular mass at risk distal to a stenosis could be determined from the corresponding fraction of total coronary artery tree length independently of the scale or X-ray magnification used to measure absolute branch lengths. 3) Cross-sectional lumen area at any point in the left coronary artery tree was closely related to the size of the dependent vascular bed with a curvilinear relation similar to that observed in humans with normal coronary arteriograms. CONCLUSIONS: On coronary arteriograms, the anatomic area at risk for myocardial infarction distal to any point in the coronary artery tree can be determined from the sum of distal coronary artery branch lengths. There is a curvilinear relation between coronary artery lumen area and dependent regional myocardial mass comparable to that in humans, reflecting fundamental physical principles underlying the structure of the coronary vascular tree.

Basic structure-function relations of the epicardial coronary vascular tree. Basis of quantitative coronary arteriography for diffuse coronary artery disease.

BACKGROUND: Quantitative coronary arteriography has been validated for stenotic segments of coronary arteries. However, it does not currently account for diffuse coronary artery disease, because the normal size of the coronary artery for its distal myocardial bed size is not known and cannot be measured directly with diffuse involvement of the artery. METHODS AND RESULTS: From clinical coronary arteriograms of 12 patients without coronary artery disease (group 1) and in 17 patients with coronary artery disease (group 2), we determined by quantitative coronary arteriography 1) the relations among measured coronary artery cross-sectional lumen area, summed distal branch lengths, and regional myocardial mass distal to each point in each coronary artery; 2) the ratio of coronary artery lumen area between parent and daughter vessels at 50 bifurcations; and 3) which of three different theoretical physical principles could underlie the tree structure of the human coronary artery system, by comparing the coronary artery size, branch lengths, regional mass, and relations between parent-to-daughter lumen area ratios with those for the different theoretical physical principles to test which principle best fit the observed data and therefore which principle most probably characterizes the human coronary artery tree structure. The results showed that 1) there is a close correlation between the lumen area of a coronary artery at each point along its length and the corresponding summed distal branch lengths and regional myocardial mass in patients without and with coronary artery disease; 2) measured coronary artery lumen area in patients with coronary artery disease is diffusely 30-50% too small for distal myocardial bed size compared with normal subjects; and 3) the observed relations among coronary artery size, distal summed lengths, myocardial bed size, and parent-to-daughter size ratios are not consistent with the theoretical principle of constant mean blood flow velocity in the coronary circulation but are consistent with the principles of minimum viscous energy loss and of limited/adaptive vascular wall shear stress characterized by a 2/3 power law relating coronary artery lumen area to distal summed branch lengths and regional mass or parent-to-daughter branching ratios. CONCLUSIONS: These observations provide a basis for quantifying diffuse coronary artery disease on clinical arteriograms.

Effects of rotational atherectomy in normal canine coronary and diseased human cadaveric arteries: potential for plaque removal from distal, tortuous, and diffusely diseased vessels.

To test the hypothesis that tortuous, diseased vessels could be successfully treated with a flexible rotational atherectomy device we evaluated the BARD atherectomy device with quantitative angiography and histology in normal canine coronary arteries and diseased human below-knee amputation specimens. The mid left anterior descending and the circumflex vessels were treated in 4 dogs serially with 1 wk separating treatments. The acute and follow-up anterior descending artery size was unchanged (1.41 mm before, 1.39 mm after, and 1.59 mm at 1 week). Similar findings were obtained in the circumflex vessels. In 4 adult human amputated legs, diseased peroneal or tibial arteries were treated with a significant reduction in the percent luminal diameter stenosis from 62.75 prior to intervention to 36.5 following intervention (p = 0.021). The luminal diameter increased from 0.81 to 1.54 mm (p = 0.06). In 2 canine arteries there was histologic evidence of localized perforation of the arterial wall, but there was no angiographic evidence of perforation or dissection and no significant myocardial necrosis in the distribution of the treated vessels at 1 wk. The majority of the diseased human vessels demonstrated smoothly cut atheromas with sparing of the media. The rotational atherectomy catheter system holds promise for removal of plaque in relatively small, diffusely diseased, tortuous vessels.

Patterns in visual interpretation of coronary arteriograms as detected by quantitative coronary arteriography.

In part 1 of a three-part study, 14 novice readers and 6 experienced cardiologists interpreted phantom images of known stenosis severity. No difference between the interpretations of experienced and novice readers was detectable. Visual estimates of "moderately" severe stenosis were 30% higher than actual percent diameter stenosis. In part 2 of the study, visual interpretation of percent diameter stenosis from 212 stenoses on 241 arteriograms was compared with quantitative coronary arteriographic assessment. The visual analysis overestimated disease severity in arteries with greater than or equal to 50% diameter stenosis (except for right coronary lesions) and underestimated severity in all arteries with less than 50% diameter stenosis. Of the 241 arteriograms, 40 had quantitative and visual analysis of all three coronary arteries for assessment of significant disease. In only 62% of the cases did visual and quantitative methods agree on the presence of severe disease; visual estimates diagnosed significantly (p less than 0.05) more three-vessel disease. In part 3 of the study, comparison of percent diameter stenosis by visual estimate with quantitative coronary arteriographic assessment before and after balloon angioplasty of 38 stenoses showed that visual interpretation significantly (p less than 0.001) overestimated initial lesion severity and underestimated stenosis severity after angioplasty.

Comparison of technetium-99m teboroxime tomography with automated quantitative coronary arteriography and thallium-201 tomographic imaging.

Technetium-99m (Tc-99m) teboroxime is a new perfusion tracer that is highly extracted and rapidly cleared by the myocardium. To determine the feasibility of Tc-99m teboroxime imaging in the diagnosis of patients with suspected coronary artery disease, 30 patients underwent single photon emission computed tomography imaging with Tc-99m teboroxime (25.2 +/- 1 mCi) at peak exercise and again 60 min later at rest. All patients underwent either a thallium stress test (n = 26) or automated quantitative coronary arteriography (n = 25), or both, without intervening revascularization or infarction. Images were reviewed by two investigators who had no knowledge of clinical data. Coronary lesions with greater than or equal to 50% diameter narrowing by quantitative coronary arteriography were considered significant. Both thallium and Tc-99m teboroxime detected disease in all patients with two or three vessel disease. One vessel disease was detected with Tc-99m teboroxime in 9 of 10 patients and with thallium in 8 of 10 (p = NS). In patients without angiographically significant disease. Tc-99m teboroxime demonstrated normal perfusion in six of eight patients and thallium in three of five (p = NS). Overall, when presence or absence of disease detected by Tc-99m teboroxime or thallium was compared with quantitative coronary arteriography, there was no difference between Tc-99m teboroxime and thallium. These results suggest that Tc-99m teboroxime is comparable to thallium as an imaging agent. The rapid biologic half-life, 5.3 min, allows studies to be completed in 60 to 90 min.

Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial.

In a prospective, randomised, controlled trial to determine whether comprehensive lifestyle changes affect coronary atherosclerosis after 1 year, 28 patients were assigned to an experimental group (low-fat vegetarian diet, stopping smoking, stress management training, and moderate exercise) and 20 to a usual-care control group. 195 coronary artery lesions were analysed by quantitative coronary angiography. The average percentage diameter stenosis regressed from 40.0 (SD 16.9)% to 37.8 (16.5)% in the experimental group yet progressed from 42.7 (15.5)% to 46.1 (18.5)% in the control group. When only lesions greater than 50% stenosed were analysed, the average percentage diameter stenosis regressed from 61.1 (8.8)% to 55.8 (11.0)% in the experimental group and progressed from 61.7 (9.5)% to 64.4 (16.3)% in the control group. Overall, 82% of experimental-group patients had an average change towards regression. Comprehensive lifestyle changes may be able to bring about regression of even severe coronary atherosclerosis after only 1 year, without use of lipid-lowering drugs.