Clinical outcomes of patients more than one year following randomization in the Canadian Coronary Atherectomy Trial (CCAT).

BACKGROUND: The Canadian Coronary Atherectomy Trial (CCAT) assessed, in a randomized comparison, the clinical and angiographic outcomes following atherectomy with those following balloon angioplasty for the treatment of de novo lesions in the proximal one-third of the left anterior descending artery (LAD). Although the procedural success rate was somewhat higher and the postprocedure lumen larger in patients treated with atherectomy, lumen dimensions, restenosis rates and clinical outcomes were similar in the two groups at six months. To determine whether late differences emerged between the groups, clinical follow-up was obtained at a median of 18 (range 10 to 31) months after randomization. METHODS AND RESULTS: Patients were contacted monthly by telephone for the first six months. Subsequent follow-up information was obtained in 272 (99%) of the 274 randomized patients via a clinic visit or telephone interview with the patient and/or a relative. Additional information was obtained from the referring physician as required. There were no differences in adverse events between the two groups during follow-up. In patients randomized to atherectomy compared with balloon angioplasty, death occurred in 1.5% versus 2.2% (cardiac death 0.7% versus 0.7%); myocardial infarction in 5.1% versus 5.9% (Q wave 1.5% versus 1.5%); coronary bypass surgery in 13.1% versus 12.6%; and repeat target lesion intervention in 22.6% versus 21.5%. Persistent or recurrent Canadian Cardiovascular Society class III/IV angina not treated by a further intervention was present in 1.5% versus 2.2%. The combined end-point of death or nonfatal myocardial infarction occurred in nine (6.6%) versus 11 (8.1%) patients and any adverse cardiac event in 50 (36.5%) versus 53 (39.3%). Multivariate logistic regression indicated that unstable angina, reference vessel size and preprocedure minimum lumen diameter were the only variables independently associated with adverse events. CONCLUSIONS: The initial choice of directional atherectomy or balloon angioplasty had no impact on clinical outcome over a period of 18 months in this patient population. With either technique, just over 60% of patients with proximal LAD disease experienced sustained symptomatic improvement without an adverse event following a single procedure, and 80% achieved this status following a repeat percutaneous intervention.

The severity of coronary atherosclerosis in type 2 diabetes mellitus is related to the number of circulating triglyceride-rich lipoprotein particles.

The presence or absence of coronary artery disease (CAD) in diabetic patients has been related to the level of circulating plasma lipoproteins. This study examines whether there is a relationship between the actual severity of CAD and the plasma concentration of major classes of plasma lipoproteins (HDL, LDL, triglyceride-rich lipoproteins (TRL), and their Sf 12 to 60 and Sf 60 to 400 subfractions), particularly the numbers of lipoprotein particles, in men and women with type 2 diabetes. 174 diabetic patients (136 men, 38 women) who underwent angiography were studied. Nine specific coronary segments were scored. The population was divided into tertiles according to the angiographic severity of their coronary disease: mild CAD: coronary score 1 to 10; moderate CAD: coronary score 11 to 13; or severe CAD: coronary score 14 to 22. The main findings were that the numbers of particles (as reflected by the apoB levels) of the TRL were greater in those with moderate and severe disease than in those with mild disease (P = .001). There was a significant correlation between the coronary score and the apoB in TRL (P = .006). There were parallel but nonsignificant changes in triglyceride levels. ApoA-I was lower in patients with moderate and severe disease (P = .01). These differences were more striking in women than they were in men. There were no differences in plasma, LDL, or HDL cholesterol or in LDL apoB or Lp(a). Multiple linear regression analysis, when adjusted for sex, age, and BMI, showed that three lipid variables (TRL apoB, LDL cholesterol, and plasma apoA-I) significantly and independently predicted the coronary score. This study demonstrates that in type 2 diabetes, the severity of angiographically evaluated CAD is positively related to the numbers of TRL particles in the plasma. This relationship is stronger in women than in men, and it is independent of HDL and LDL.

Influence of stenotic lesion morphology on immediate and long-term (6 months) angiographic outcome: comparative analysis of directional coronary atherectomy versus standard balloon angioplasty.

OBJECTIVES: This study sought to determine whether preprocedural lesion morphology differentially affects the outcome of directional coronary atherectomy versus standard balloon angioplasty. BACKGROUND: Despite previous studies (Canadian Coronary Atherectomy Trial [CCAT]/Coronary Angioplasty Verus Excisional Atherectomy Trial [CAVEAT]), directional coronary atherectomy continues to be recommended on the basis of lesion-specific features, although the validity of this approach has never been proved. METHODS: A retrospective, subgroup analysis of the CCAT data base (group average +/- SD) was performed. RESULTS: In the long term (6 months), both procedures were equally successful in the proximal left anterior descending coronary artery (directional atherectomy 0.62 +/- 0.70 mm vs. coronary angioplasty 0.70 +/- 0.72 mm, p = NS), with atherectomy tending to perform best in relatively "simple" lesions (American College of Cardiology/American Heart Association [ACC/AHA] type A: atherectomy 0.57 +/- 0.70 mm vs. angioplasty 0.50 +/- 0.77 mm; ACC/AHA type B1: atherectomy 0.65 +/- 0.68 mm vs. angioplasty 0.60 +/- 0.68 mm) and those with moderate dystrophic calcification (atherectomy 0.79 +/- 0.56 mm vs. angioplasty 0.45 +/- 0.73 mm). Although greatest minimal lumen diameter gains were seen in larger (> 3 mm) coronary arteries (atherectomy 0.76 +/- 0.62 mm vs angioplasty 0.80 +/- 0.72 mm, p = NS) and those with severe obstruction (preprocedural minimal lumen diameter < 1.0 mm: atherectomy 0.80 +/- 0.62 mm vs. angioplasty 0.84 +/- 0.63 mm, p = NS), neither technique was superior, and eccentric stenoses (symmetry index < 0.5) had similar outcomes (atherectomy 0.59 +/- 0.49 mm vs. angioplasty 0.62 +/- 0.65 mm, p = NS). CONCLUSIONS: These data refute many preconceptions regarding the choice of directional coronary atherectomy on the basis of anatomic criteria.

Initial report of rotational ablation: the Toronto Hospital experience.

OBJECTIVE: To describe the initial experience of rotational ablation (using the Rotablator device), in terms of safety and the effectiveness as a proportion of final angiographic outcome when combined with adjunctive balloon angioplasty. DESIGN: Retrospective analysis of single-centre experience, including operator learning curve. SETTING: Tertiary care hospital, Cardiac Catheterization Laboratory. PATIENTS: Consecutive subjects (14 men, 11 women) selected for rotational ablation based on ostial/bifurcation lesions (n = 10), 'long' (more than 10 mm) stenoses (n = 11) or extensive dystrophic calcification (n = 4). INTERVENTIONS: Rotational ablation (Rotablator) with routine adjunctive balloon angioplasty. Quantitative coronary arteriography using the Cardiac Measurement System. RESULTS: Rotational ablation reduced coronary obstruction, as demonstrated by minimal lumen diameter (preprocedure, 0.57 =/- 0.28 to 1.17 +/- 0.32 mm, P<0.05), with further improvements following adjunctive balloon angioplasty (1.93 +/- 0.35 mm). Similar changes were observed in relative stenosis after Rotablator (preprocedure, 79.7 +/- 7.6 to 56.1 +/- 13.1% diameter), with typical post-angioplasty residual narrowings (29.7 +/- 8.2% diameter). Estimated stenotic flow reserve was improved by the interventional procedures (preprocedure, 0.94 +/- 0.70; rotational ablation 3.07 +/- 1.14; and angioplasty, 4.73 +/- 0.25 times baseline). Complications were acceptable, and included three acute occlusions requiring balloon angioplasty recanalization and three non-Q wave myocardial infarctions (with creatine phosphokinase levels of 270, 417 and 602 IU, respectively). CONCLUSIONS: The Rotablator is a relatively user-friendly device with a reasonable safety profile, accounting for approximately 50% of minimum lumen diameter gains when used in conjunction with routine balloon angioplasty. The precise role of rotational ablation, particularly in the context of preselected lesion specific uses (bifurcations, long lesions, dystrophic calcification), requires prospective, randomized studies.

Analysis of atherosclerotic plaques obtained by coronary atherectomy: Foam cells correlated positively with subsequent restenosis.

Restenosis following coronary intervention is a complex process the mechanisms of which remains mostly unknown. Tissue obtained by atherectomy is an important means to study restenosis. Previous studies on atherectomy-retrieved tissue have not identified histologic features that correlate with restenosis. We performed an histopathologic evaluation on atherosclerotic plaque tissue obtained by atherectomy from 58 patients, all of whom had a 6-month angiographic follow-up. We identified macrophages and lymphocytes and localized tumor necrosis factor-α expression in the tissue by immunohistochemistry. Histopathology was correlated with late angiographic outcomes. Of 10 histologic features evaluated in the plaque tissue, only the presence of foam cells, identified in paraffin sections, correlated positively with restenosis (p = 0.04). Immunohistochemistry showed that macrophages (p = .07), tumor necrosis factor-α (p = .07), and lymphocytes (p = .14) were more prominent, but not significantly so, in lesions from patients with foam cells and restenosis than in lesions from patients without foam cells or restenosis. Thus the presence of foam cells in primary lesions obtained by atherectomy as identified in paraffin-embedded tissue appears to be a marker for restenosis.

Hypertrophic cardiomyopathy. Clinical spectrum and treatment.

HCM is a heterogeneous disease genotypically, phenotypically, pathophysiologically, clinically, and therapeutically. In decisions on the management of these patients, it is important to recognize this heterogeneity and to direct therapy at the predominant abnormalities.

Comparative analysis of saphenous vein bypass vs. native coronary artery balloon angioplasty: technical differences and angiographic response.

To evaluate technical differences and angiographic response of saphenous vein bypass graft angioplasty in comparison to native coronary arteries, we retrospectively analyzed 54 patients undergoing this procedure at The Toronto Hospital between February 1988 and May 1993. These subjects were temporally matched to a cohort of successful native coronary angioplasties, with comparison of technical parameters, pre-existing qualitative/quantitative (Cardiac Measurement System) stenotic morphology, and angiographic response; including changes in minimum lumen diameter. Saphenous bypass graft angioplasty utilized larger balloons (CABG, 3.27 +/- 0.65 vs. native, 2.90 +/- 0.37 mm, P < .05), and higher inflation pressures (CABG, 10.1 +/- 3.7 vs. native, 8.8 +/- 2.5 atm, P < .05), although in a relative sense, balloon/artery ratios were similar (CABG, 1.09 +/- 0.20 vs. native, 1.03 +/- 0.15, pNS). Pre-procedural bypass graft lesions were more complex, with more frequent ACC/AHA type B1 lesions [CABG, 24/54 (44%) vs. native, 16/54 (30%), P < .05] and luminal thrombus [CABG, 17/54 (31%) vs. native, 6/54 (11%), P < .05]. Quantitative angiography revealed larger "reference" diameters within saphenous veins (CABG, 3.41 +/- 0.76 vs. native, 3.04 +/- 0.51 mm, P < .05), although minimum lumen diameter was less severe (CABG, 0.83 +/- 0.41 vs. native, 0.77 +/- 0.36, P < .05). In terms of balloon angioplasty response, greater improvement in luminal diameter was seen in bypass graft lesions (CABG, 1.55 +/- 0.53 vs. native, 1.32 +/- 0.44 mm, P < .05), with the largest changes within the "body" of the saphenous vein (ostial, 1.53 +/- 0.37; body, 1.68 +/- 0.50; anastomosis, 1.37 +/- 0.57 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Systematic bias in the reporting of angioplasty outcomes: accuracy of visual estimates of absolute lumen diameters.

To examine physician bias in reporting percutaneous transluminal coronary angioplasty (PTCA) results and analyze this potential source of errors, and to examine the ability to estimate absolute lumen diameters visually, the authors reviewed 56 successful PTCAs from their institution. Pre- and postprocedural cineangiograms were blindly reviewed by an experienced consensus panel (three members) and compared with the interventional cardiologist's reported outcome (percentage diameter stenosis) and quantitative coronary angiography (QCA) using the Cardiac Measurement System. Staff cardiologists significantly overestimated pre-PTCA stenosis severity (staff 83.7 versus panel 75.2%, P < 0.05) while underestimating residual narrowing (staff 18.4 versus panel 22.8%, P < 0.05), thus exaggerating overall angioplasty benefit (staff -65.3 versus panel -52.4%, P < 0.05). The cumulative error varied greatly among individual staff members (3.4 to 18.0%). Despite these findings, the consensus panel accurately identified pre-PTCA minimum lumen diameter, as measured by quantitative angiography (panel 0.66 versus QCA 0.67 mm, not significant), although they tended to overestimate absolute postprocedural luminal dimensions (panel 2.28 versus QCA 2.00 mm, P < 0.05) and thereby ultimate changes in minimum lumen diameter (panel 1.62 versus QCA 1.33 mm, P < 0.05). Therefore, substantial bias exists in the reporting of PTCA outcomes, which tends to magnify the perceived benefits of the procedure. Well-trained observers can accurately estimate pre-PTCA absolute lumen diameters, although difficulties occur in evaluating residual dimensions.

A comparison of directional atherectomy with balloon angioplasty for lesions of the left anterior descending coronary artery.

BACKGROUND: Restenosis is a major limitation of coronary angioplasty. Directional coronary atherectomy was developed with the expectation that it would provide better results than angioplasty, including a lower rate of restenosis. We undertook a randomized, multicenter trial to compare the rates of restenosis for atherectomy and angioplasty when used to treat lesions of the proximal left anterior descending coronary artery. METHODS: Of 274 patients referred for first-time, non-surgical revascularization of lesions of the proximal left anterior descending coronary artery, 138 were randomly assigned to undergo atherectomy and 136 to undergo angioplasty; 257 of 265 eligible patients (97 percent) underwent follow-up angiography at a median of 5.9 months. Computer-assisted quantitative measurements of luminal dimensions were determined from the angiograms obtained before and immediately after the procedure and at follow-up. The primary end point of restenosis was defined as stenosis of more than 50 percent of the vessel's diameter at follow-up. RESULTS: Quantitative analysis showed that the procedural success rate was higher in patients who underwent atherectomy than in those who had angioplasty (94 percent vs. 88 percent, P = 0.061); there was no significant difference in the frequency of major in-hospital complications (5 percent vs. 6 percent). At follow-up, the rate of restenosis was 46 percent after atherectomy and 43 percent after angioplasty (P = 0.71). Despite a larger initial gain in the minimal luminal diameter with atherectomy (mean [+/- SD], 1.45 +/- 0.47 vs. 1.16 +/- 0.44 mm; P < 0.001), there was a larger late loss (0.79 +/- 0.61 vs. 0.47 +/- 0.64 mm; P < 0.001), resulting in a similar minimal luminal diameter in the two groups at follow-up (1.55 +/- 0.60 vs. 1.61 +/- 0.68, P = 0.44). The clinical outcomes at six months were not significantly different between the two groups. CONCLUSIONS: The role of atherectomy in percutaneous coronary revascularization remains to be fully defined. However, as compared with angioplasty, atherectomy did not result in better late angiographic or clinical outcomes in patients with lesions of the proximal left anterior descending coronary artery.

Acute dose-response effects of intravenous disopyramide in hypertrophic obstructive cardiomyopathy.

To evaluate the acute hemodynamic effects of intravenous disopyramide in hypertrophic obstructive cardiomyopathy (HOCM), 25 patients (12 men, 13 women) with an average age of 40 years (range 18 to 70 years) were evaluated while undergoing cardiac catheterization-angiography. Biplane left ventricular angiography was performed with standard intracardiac-systemic hemodynamics, including resting and provoked (after ventricular premature beat) left ventricular outflow tract gradients, by using simultaneous LV and aortic pressures as disopyramide was being administered (total dose 100 mg, bolus 10 mg every 3 minutes). Average baseline thermodilution cardiac output equalled 4.5 +/- 1.2 L/min, with all 25 subjects demonstrating systolic anterior motion of the mitral apparatus (mild, 3 [12%]; moderate, 8 [32%]; severe, 14 [64%]). Although heart rate originally slowed during disopyramide administration, average heart rate increased during the final stages (before, 78 +/- 15 vs after, 82 +/- 13 beats/min; p < 0.05). Systemic aortic pressures increased during intravenous disopyramide (before, 107 +/- 21/71 +/- 19 mm Hg vs after, 120 +/- 28/81 +/- 13 mm Hg; p < 0.05), with a decline in LV end-diastolic pressure (before, 19 +/- 7 vs after, 16 +/- 6 mm Hg; p < 0.01). Maximum LV systolic pressures decreased (before, 193 +/- 32 vs after, 146 +/- 29 mm Hg; p < 0.01), with a substantial reduction in resting LV outflow tract gradients (before, 86 +/- 34 vs after, 27 +/- 20 mm Hg; p < 0.001) in conjunction with less inducible obstruction (before, 124 +/- 33 vs after, 64 +/- 33 mm Hg; p < 0.001). Only minor electrocardiographic changes were seen during disopyramide infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Early experience with directional coronary atherectomy: documentation of the learning curve.

OBJECTIVE: To evaluate evolving selection criteria and angiographic outcome ('learning curve') for directional coronary atherectomy. SETTING: Tertiary referral, university-based hospital. PATIENTS: Initial 50 subjects undergoing directional coronary atherectomy of de novo left anterior descending stenoses at The Toronto Hospital from July 1990 to April 1991. INTERVENTIONS: Directional coronary atherectomy according to standard interventional techniques, with pre- and post procedure qualitative evaluation and quantitative coronary arteriography (Cardiac Measurement System; Leiden, The Netherlands) to define angiographic outcome. RESULTS: Comparing 'early' (group 1) versus 'late' (group 2) subjects, baseline demographics and clinical parameters were similar. Later subjects demonstrated increased coronary tortuosity (group 1, 1.40 versus group 2, 1.64, P < 0.01) and major side branch involvement within the stenosis (group 1, seven of 25 [28%] versus group 2, 18 of 25 [72%], P < 0.01). Regardless of experience, post procedure residual minimum stenotic diameters were equal (group 1, 2.75 +/- 0.55 versus group 2, 2.49 +/- 0.42 mm) in progressively longer lesions (group 1, 11.4 +/- 4.9 versus group 2, 13.3 +/- 5.5 mm, P < 0.1), with increased symmetry (group 1, 0.60 +/- 0.28 versus group 2, 0.73 +/- 0.19, P < 0.05). Analysis of consecutive pentiles (10 subjects per group) indicated gradual increases in post procedure residual lumen during early experience (the first 30 subjects), with an abrupt deterioration in outcome (fourth pentile), secondary to qualitative changes in coronary anatomy, before a return to satisfactory residual minimum stenotic diameters (fifth pentile). CONCLUSIONS: This study defines a distinct 'learning curve' during the initial 30 patients undergoing directional coronary atherectomy, with subtle changes in case selection, predominantly reflected by qualitative indices (eg, tortuosity, dystrophic calcification), resulting in a transient deterioration in final outcomes (patient 31 to 40). Subsequently, optimal results were re-established after defining appropriate case selection criteria, in conjunction with progressive expertise.

Acute outcome of directional coronary atherectomy vs standard balloon angioplasty in de novo left anterior descending stenoses.

To assess the immediate outcome of directional coronary atherectomy (DCA) versus standard balloon angioplasty (PTCA) in de novo left anterior descending coronary stenoses, 25 consecutive atherectomies (22 men, 3 women) performed at The Toronto Hospital, between July 1990 and March 1991 were compared with 25 (14 men, 11 women) temporally matched successful angioplasties. Coronary stenoses were analyzed by quantitative arteriography, using the Coronary Measurement System (Leiden, The Netherlands), with estimation of transstenotic hemodynamics by fluid dynamic equations. Before and after procedure qualitative blood flow (TIMI criteria) was also evaluated, as was intimal haziness and coronary dissection. In comparison to PTCA, coronary atherectomy produced less residual minimum stenotic diameter (DCA, 2.75 +/- 0.55 vs PTCA, 1.70 +/- 0.44 mm, p < 0.001), and relative percent diameter stenosis (DCA, 17.9 +/- 10.7 vs PTCA, 34.4 +/- 10.7 percent, p < 0.001), with less transstenotic obstructive gradient (DCA, 0.2 +/- 0.2 vs PTCA, 1.0 +/- 1.5 mm Hg, p < 0.05), and greater estimated stenotic flow reserve (DCA, 4.86 +/- 0.15 vs PTCA, 4.50 +/- 0.48 x baseline, p < 0.05). Coronary atherectomy "normalized" TIMI flow patterns in virtually all patients (DCA, 2.96 +/- 0.20 vs PTCA, 2.72 +/- 0.45, p < 0.05), while creating less intimal haziness (DCA, 10/25 [40 percent] vs PTCA, 23/25 [92 percent], p < 0.01), and coronary dissection (DCA, 6/25 [24 percent] vs PTCA, 16/25 [64 percent], p < 0.05). Therefore, when compared with standard balloon angioplasty, DCA produces less residual stenosis, better transstenotic hemodynamics, while decreasing the frequency of coronary artery damage, in de novo left anterior descending stenoses.

Comparison of acute elastic recoil after directional coronary atherectomy versus standard balloon angioplasty.

We evaluated intraprocedural "elastic recoil" in 25 patients (22 men and 3 women) undergoing directional coronary atherectomy (DCA) of left anterior descending stenoses, and compared these with 25 temporally-matched (14 men and 11 women) patients having balloon angioplasties (PTCA). Quantitative arteriography was performed using the Coronary Measurement System (Leiden, The Netherlands), with "elastic recoil" defined as the difference in maximum device or balloon size minus residual minimum diameter. In addition, we determined the effects of relative device size, specific anatomic location (proximal/mid artery), lesion length, eccentricity (symmetry index), and dystrophic calcification on acute "recoil" severity after both procedures. Although initial coronary stenoses were similar (minimum stenotic diameter, DCA = 0.59 +/- 0.20 mm versus PTCA = 0.55 +/- 0.23 mm, p = NS), less "elastic recoil" was observed after atherectomy (DCA = 0.83 +/- 0.57 mm versus PTCA = 1.26 +/- 0.56 mm, p < 0.01), and this was confirmed by absolute recoil/maximum device size ratios (DCA = 23.5 +/- 16.0% versus PTCA = 41.6 +/- 13.8%, p < 0.01). Acute "elastic recoil" was also influenced by maximum device size/"normal" coronary artery ratios [(ratio < 0.9, DCA = 0.26 +/- 0.10 mm versus PTCA = 0.84 +/- 0.13 mm, p < 0.01); (ratio 0.9 to 1.1, DCA = 0.69 +/- 0.41 mm versus PTCA 0.75 +/- 0.32 mm, p = NS); (ratio > 1.1, DCA = 1.09 +/- 0.64 mm versus PTCA = 1.59 +/- 0.48 mm, p < 0.05)].(ABSTRACT TRUNCATED AT 250 WORDS)

Directional coronary atherectomy at the Toronto and Mount Sinai Hospitals: report of the initial 120 procedures.

OBJECTIVE: To assess the procedural success and complication rates of the first 120 directional coronary atherectomy cases performed at two Toronto hospitals. DESIGN AND SETTING: Case series in tertiary referral centres. PATIENTS: One hundred and thirteen patients in whom 120 atherectomy procedures were attempted between July 1990 and April 1992. INTERVENTION: Directional coronary atherectomy. MAIN RESULTS: Angiographic success was obtained in 115 of 120 procedures (96%) involving 117 of 123 lesions (95%). Procedural success (angiographic success without death, myocardial infarction or coronary bypass surgery) was obtained in 110 of 120 procedures (92%). Adjunctive balloon angioplasty was required in 20 procedures (17%). There was one death at 36 h in an elderly patient who underwent an emergency procedure while in cardiogenic shock. Periprocedural non-Q wave myocardial infarction occurred in five patients. There were no Q wave myocardial infarctions. Three patients required coronary bypass surgery prior to discharge and vascular complications occurred in five patients. CONCLUSIONS: Directional coronary atherectomy can be performed with procedural success and complication rates comparable to conventional balloon angioplasty. Randomized trials are underway to determine if atherectomy results in a lower restenosis rate.

Residual coronary stenoses and calculated transstenotic gradients after intravenous streptokinase versus tissue plasminogen activator.

To compare the relative success of intravenous streptokinase (STK) and tissue plasminogen activator (TPA) on the severity of residual infarct-related coronary stenoses, we evaluated 45 patients receiving thrombolytic therapy for acute myocardial infarction. Twenty-three patients (18 men and 5 women) received STK (1.5 million units), while 22 patients (18 men and 4 women) received TPA (100 mg) within 6 hours of chest discomfort. Cardiac catheterization was performed before hospital discharge (8 days) with quantitative coronary arteriography and estimation of transstenotic pressure gradients using fluid dynamic equations. Although angina pectoris was equally common (STK, 7 of 23 [30%] versus TPA, 5 of 22 [23%], p = NS), recurrent infarction (STK, 3 of 23 [13%] versus TPA, 7 of 22 [32%], p less than 0.05) and coronary angioplasty (STK, 2 of 23 [9%] versus TPA, 7 of 22 [32%], p less than 0.05) were more frequent in those receiving TPA. Infarct-related coronary patency was greater in TPA-treated subjects (STK, 15 of 23 [65%] versus TPA, 19 of 22 [86%], p less than 0.05), although minimum stenotic diameter (STK, 0.77 +/- 0.48 mm versus TPA, 0.57 +/- 0.38 mm, p less than 0.05), and calculated transstenotic pressure gradient (STK, 8.7 +/- 17.0 mm Hg versus TPA, 23.7 +/- 30.2 mm Hg, p less than 0.05) suggested severe residual stenosis. These effects were accentuated at elevated coronary flow velocities (8 to 20 cm/sec).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic features associated with acute coronary artery occlusion during elective angioplasty.

To examine the morphologic features of stenotic segments developing abrupt coronary occlusion during elective angioplasty, 36 cases occurring at the Toronto General Hospital between January 1985 and December 1989 were evaluated and compared with a temporally matched successful group. Quantitative arteriographic analysis was performed, including estimates of arterial tortuosity (proximal-stenotic axis deviation) and qualitative assessment for dystrophic calcification, residual lumen eccentricity and intimal irregularity. Acute occlusion occurred more frequently in the mid-arterial segment (success, mid 14 versus occlusion 21, P less than 0.05). Stenosis severity assessed by minimum stenotic diameter did not affect outcome (success 0.42 mm versus occlusion 0.37 mm, not significant or relative percentage diameter stenosis (success 86% versus occlusion 86%, not significant). Average stenotic length was equal (success 14.3 mm versus occlusion 13.6 mm, not significant), although coronary arterial tortuosity was increased in the acute occlusion group (success 27 degrees versus occlusion 34 degrees, P less than 0.05). Residual lumen eccentricity score was increased (success 1.66 versus occlusion 2.69, P less than 0.001), with greater dystrophic calcification in the occlusion group (success 0.31 versus occlusion 0.69, P less than 0.05). In addition, intimal irregularity was significantly greater (success 1.65 versus occlusion 2.5, P less than 0.001), although major arterial side branches failed to predict outcome (success 28% versus occlusion 36%, not significant). These data suggested that a mid-coronary anatomic location, arterial tortuosity, lumen eccentricity, dystrophic calcification and intimal irregularity increased the probability of acute occlusion during elective coronary angioplasty.

Effect of intracoronary nifedipine on coronary bloodflow and myocardial metabolism during pacing-induced ischemia.

The effects of intracoronary nifedipine on coronary bloodflow, its regional distribution, myocardial oxygen consumption and lactate metabolism during pacing-induced angina were evaluated in 15 subjects. These responses were directly compared to 10 subjects who received an alcohol-based control solvent. Myocardial bloodflow was measured by thermodilution, with changes in regional coronary flow assessed using a dual radiolabelled (technetium-99m and indium-111) intracoronary microsphere technique and single photon emission tomography. Neither intracoronary nifedipine (100 micrograms) or the control solvent produced changes in systemic arterial pressure (nifedipine -2 mmHg and control +2 mmHg, both not significant). Intracoronary nifedipine markedly increased left ventricular end diastolic pressure (pre-nifedipine 13.0 mmHg versus post nifedipine 20.1, P less than 0.05), while increasing total coronary sinus bloodflow (pre-nifedipine 134 mL/min versus post nifedipine 189, P less than 0.05): Regional coronary bloodflow increased in all myocardial segments, regardless of the severity of coronary stenosis (64 to 132% baseline, all P less than 0.05). In addition, intracoronary nifedipine increased myocardial oxygen consumption (pre-nifedipine 12.3 mL/min versus post nifedipine 15.7, P less than 0.05), with a trend towards improved lactate extraction (pre-nifedipine 0.24 mg/mL versus post nifedipine 0.12, not significant). Although decreased ventricular afterload (left ventricular systolic wall stress) may contribute to nifedipine's antianginal properties, a primary increase in regional coronary bloodflow also appears to be an important factor in the alleviation of myocardial ischemia.

Changes in diameter of coronary narrowings and translesional hemodynamics after intracoronary nitroglycerin.

The effect of intracoronary nitroglycerin on coronary stenosis dimensions and translesional hemodynamics was evaluated in 38 subjects (74 stenoses) referred for diagnostic coronary arteriography. Quantitative coronary arteriography was performed with standard Newtonian fluid dynamic equations used to estimate transstenotic gradients. Since intracoronary nitroglycerin can induce significant myocardial hyperemia (increased flow velocity), with increased translesional pressure gradients and a decrease in distal intraluminal pressure, the potential effect on subendocardial flow distribution was also analyzed. Minimum stenotic diameter significantly increased postnitroglycerin (NTG) (preNTG 1.42 vs postNTG 1.82 mm, p less than 0.01), with a decrease in relative percent diameter stenosis (preNTG 45.7 vs postNTG 40.7%, p less than 0.05). When changes in minimum stenotic diameter were analyzed according to stenosis severity (quartiles), the greatest effect was noted in those lesions with the least severe stenosis (quartile no. 1, 0.49 vs quartile no. 4, 0.32 mm, p less than 0.05). If coronary blood flow velocity remains at baseline values (4 cm/s), intracoronary nitroglycerin was predicted to significantly decrease transstenotic pressure gradients (preNTG 1.01 vs postNTG 0.82 mm Hg, p less than 0.05), with the greatest change shown in severe lesions (quartile no. 4, preNTG 3.79 to postNTG 2.28 mm Hg, p less than 0.01). Accelerated coronary flow velocity (myocardial hyperemia) increased calculated translesional pressure gradients (4 cm/s, 0.82 mm Hg vs 20 cm/s, 8.00 mm Hg, p less than 0.01), despite simultaneous stenotic vasodilation. Hemodynamic obstruction was particularly dependent on coronary flow velocity in the most severe stenoses (quartile no. 4, 4 cm/s, 2.28 vs 20 cm/s, 28.78 mm Hg, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Preservation of left ventricular performance with reduced ischemic dysfunction by intravenous nisoldipine.

The effect of intravenous nisoldipine on cardiac performance was examined during pacing-induced ischemia in 14 patients with coronary artery disease. The relative contributions of afterload reduction or prevention of myocardial ischemia were assessed using load-independent global (peak-systolic pressure/end-systolic volume) and regional (peak-systolic pressure/end-systolic radial length) "contractile" indexes. Nisoldipine decreased aortic pressure (predrug, 109 +/- 14 vs postdrug, 88 +/- 13 mm Hg, p less than 0.01) and prevented elevation of left ventricular end-diastolic pressure during rapid atrial pacing (predrug, 7.9 +/- 5.7 vs postdrug, -0.5 +/- 4.9 mm Hg, p less than 0.001). Resting cardiac index (predrug, 3.3 +/- 0.6 vs postdrug, 4.2 +/- 0.7 liters/min/m2, p less than 0.05), and left ventricular ejection fraction (predrug, 68.1 +/- 9.0 vs postdrug, 74.2 +/- 9.4%, p less than 0.05) increased after nisoldipine, which also prevented the deterioration in left ventricular ejection fraction (predrug, -8.1 +/- 7.9 vs postdrug, -1.0 +/- 3.7%, p less than 0.05) and fractional radial shortening (predrug, -8.7 +/- 13.1 vs postdrug, 3.7 +/- 16.4%, p less than 0.01) during rapid atrial pacing. Under these conditions, nisoldipine preserved myocardial function, as determined by global peak-systolic pressure/end-systolic volume (predrug, -0.82 +/- 0.39 vs postdrug, 0.17 +/- 1.54 mm Hg/ml, p less than 0.05) and regional (peak-systolic pressure/end-systolic radial length, predrug, -23.8 +/- 36.1 vs postdrug, 12.7 +/- 36.3 mm Hg/cm, p less than 0.01) "contractile" indexes. Intravenous nisoldipine maintains ventricular performance during rapid atrial pacing via a combination of systemic vasodilation and amelioration of ischemic myocardial dysfunction.

Validation of left ventricular function parameters acquired with the non-imaging nuclear probe: comparison with tantalum marker cine-fluoroscopy.

We evaluated the accuracy of the non-imaging nuclear probe for measuring various parameters of left ventricular function by comparing these with simultaneous measurements acquired via tantalum marker cine-fluoroscopy. Eight patients with surgically implanted mid-myocardial tantalum markers were studied during cardiac catheterization. High temporal resolution tantalum marker-derived volume/time curves were generated and calibrated to absolute endocardial volumes by comparison with contrast left ventricular angiography. Left ventricular function parameters were acquired at baseline and during atrial pacing, nitroprusside infusion and volume loading. Simultaneous measurements obtained with the nuclear probe and via tantalum marker cine-fluoroscopy were compared. The following correlation coefficients were obtained: ejection fraction, r = 0.49, P less than 0.001; peak ejection rate, r = 0.41, P less than 0.01; mean ejection rate, r = 0.62, P less than 0.001; time to peak ejection, r = 0.73, P less than 0.001; peak filling rate, r = 0.73, P less than 0.001; time to peak filling, r = 0.58, P less than 0.001. Relative changes in end-diastolic volume were accurately tracked by the nuclear probe in six of seven patients (r values 0.77-0.93). These results suggest that measurements of certain left ventricular volume parameters with the nuclear probe may not accurately reflect true volume changes as measured by tantalum marker cine-fluoroscopy. Although, the probe may be useful in tracking relative changes in end-diastolic volume, we would advise caution in using this instrument for studies requiring accurate measurements of ejection and filling parameters.