Impact of coronary revascularization vs medical therapy on ischemia among stable patients with or suspected coronary artery disease undergoing serial myocardial perfusion scintigraphy.

BACKGROUND: Randomized trials have challenged the role of revascularization in stable coronary artery disease. We aimed to appraise the impact of revascularization on ischemia in patients undergoing serial myocardial perfusion scintigraphy (MPS). METHODS: We queried our institutional database for stable subjects undergoing serial MPS and appraised the impact of revascularization on changes in ischemia. RESULTS: A total of 3631 patients were included: 967 (27%) undergoing revascularization and 2664 (73%) receiving medical therapy only. Patients treated with revascularization had a significantly lower burden of myocardial ischemia at follow-up (odds ratio = 0.577 [95% confidence interval 0.483-0.689] vs medical therapy, P < .001). Among all those having moderate or severe ischemia at baseline, revascularization was associated with a follow-up prevalence of 80% for no, minimal, or mild ischemia and 20% for moderate or severe ischemia, vs 43% and 57% for medical therapy (P < .001). Even at multivariable analysis and propensity-adjusted, and propensity-matched analyses, revascularization was associated with a significantly lower prevalence of moderate or severe ischemia at follow-up (respectively P < .001, P = .001, and P = .042). CONCLUSIONS: Revascularization appears superior to medical therapy in reducing ischemic burden and normalizing myocardial perfusion among subjects with moderate or severe ischemia at baseline.

Comparative Impact of Hypoglycemic Agents on Severity and Extent of Myocardial Ischemia in Patients With Type 2 Diabetes Mellitus Undergoing Myocardial Perfusion Scintigraphy.

BACKGROUND: Hypoglycemic agents differ in mechanism, efficacy, and profile. However, there is uncertainty on their impact on myocardial perfusion. We thus aimed to investigate whether individuals with type 2 diabetes mellitus treated with different drug classes exhibit different perfusion patterns at myocardial perfusion scintigraphy (MPS). METHODS AND RESULTS: We queried our administrative database for patients with diabetes mellitus without prior or recent myocardial infarction. The primary objective was to compare the severity and extent of ischemia at MPS, distinguishing patients according to management strategy. A total of 7592 patients were included [2336 (31%) on diet, 3611 (48%) on metformin, 749 (10%) on sulfonylureas, 449 (6%) on metformin plus sulfonylureas, 447 (6%) on metformin plus insulin]. Unadjusted analyses and analyses adjusting for baseline features suggested that sulfonylureas alone or in combination were associated with more severe ischemia than nonsulfonylurea regimens (P < 0.05), whereas combination regimens including metformin were associated with more extensive myocardial ischemia than the other regimens (P < 0.05 for both). However, no significant difference disfavoring either metformin or sulfonylurea regimens persisted after multivariable adjustment for baseline, stress, and angiographic characteristics (all P > 0.05). CONCLUSION: Several significant differences in baseline, stress, and scintigraphic features appear evident in patients with diabetes mellitus receiving different hypoglycemic agents or regimens.

Prognostic impact of location and extent of vessel-related ischemia at myocardial perfusion scintigraphy in patients with or at risk for coronary artery disease.

BACKGROUND: Myocardial perfusion scintigraphy (MPS) has an established diagnostic and prognostic role in patients with or at risk for coronary artery disease, with ischemia severity and extent having already been identified as key predictors. Whether this is affected by the location of myocardial ischemia is uncertain. We aimed at comparing the prognostic outlook of patients undergoing MPS according to the site of ischemia. METHODS: Our institutional database was queried for subjects undergoing MPS, without myocardial necrosis or recent revascularization. We focused on the prognostic impact of location of vessel-related ischemia (VRI) at MPS, distinguishing four mutually exclusive groups: single-VRI involving left anterior descending (LAD), single-VRI not involving LAD, multi-VRI involving LAD, and multi-VRI not involving LAD. The primary outcome was the long-term (>1 year) rate of death or myocardial infarction (D/MI). RESULTS: A total of 13,254 patients were included. Moderate or severe VRI occurred in 2,627 (20%) patients. Clinical outcomes were significantly different among the groups of patients with moderate or severe VRI, including death, cardiac death, non-fatal myocardial infarction or their composites (overall P < .001). Specifically, and excluding subjects undergoing revascularization as first follow-up event, D/MI occurred in 8.4% of patients with single-VRI involving LAD, 5.5% of subjects with single-VRI not involving LAD, 16.5% of those with multi-VRI involving LAD, and 7.3% of patients with multi-VRI not involving LAD (overall P < .001). Even at incremental multivariable Cox proportional analysis, hierarchical VRI was independently associated with an increased risk of D/MI [hazard ratio = 1.17 (1.04-1.08) for each class increment, P = .010]. CONCLUSIONS: Location and extent of myocardial ischemia at MPS according to the VRI concept have a hierarchical predictive impact, with multi-VRI involving LAD being significantly and independently more prognostically ominous than other types of VRI.

Time to and risk of cardiac events after myocardial perfusion scintigraphy.

BACKGROUND: The burden of cardiovascular disease is increasing, yet it remains difficult to focus preventive strategies on populations at highest absolute and relative risks. We compared absolute and relative cardiovascular event counts, plus time to first event, among patients undergoing myocardial perfusion scintigraphy (MPS). METHODS AND RESULTS: Our database was queried to identify subjects without myocardial necrosis or recent revascularization, focusing on cardiac death (CD) or myocardial infarction (MI). A total of 13,254 patients were included, 5436 (41%) without, and 7818 (59%) with ischemia. After 32±21 months, subjects without ischemia, compared to those with ischemia, had lower absolute (16 vs 75 events, 18% vs 82%, p<0.001) and relative (0.3% vs 1.3%, p<0.001) risk of CD. Similar findings were obtained for MI (52 vs 81 events, 39% vs 61%, p<0.001, with corresponding rates of 1.0% vs 1.4%, p<0.001, respectively). Medical therapy appeared associated with fewer outcomes in those without ischemia, with the opposite occurring for subjects with ischemia (p<0.001). Median times to event ranged between 13 and 25 months in patients without ischemia vs 2 and 14 months in those with ischemia (p<0.001 for all comparisons). Multivariable-adjusted and propensity matched analyses confirmed the independent prognostic role of myocardial ischemia and, apparently, revascularization. CONCLUSION: Most fatal and non-fatal cardiac events appear to occur in patients with evidence of myocardial ischemia at MPS, especially those with moderate or severe ischemia not receiving revascularization during follow-up.

A novel clinically relevant segmentation method and corresponding maximal ischemia score to risk-stratify patients undergoing myocardial perfusion scintigraphy.

BACKGROUND: Myocardial perfusion scintigraphy (MPS) represents a key prognostic tool, but its predictive yield is far from perfect. We developed a novel clinically relevant segmentation method and a corresponding maximal ischemia score (MIS) in order to risk-stratify patients undergoing MPS. METHODS: Patients referred for MPS were identified, excluding those with evidence of myocardial necrosis or prior revascularization. A seven-region segmentation approach was adopted for left ventricular myocardium, with a corresponding MIS distinguishing five groups (no, minimal, mild, moderate, or severe ischemia). The association between MIS and clinical events was assessed at 1 year and at long-term follow-up. RESULTS: A total of 8,714 patients were included, with a clinical follow-up of 31 ± 20 months. Unadjusted analyses showed that subjects with a higher MIS were significantly different for several baseline and test data, being older, having lower ejection fraction, and achieving lower workloads (P < .05 for all). Adverse outcomes were also more frequent in patients with higher levels of ischemia, including cardiac death, myocardial infarction (MI), and their composites (P < .05 for all). Differences in adverse events remained significant even after extensive multivariable adjustment (hazard ratio for each MIS increment = 1.57 [1.29-1.90], P < .001 for cardiac death; 1.19 [1.04-1.36], P = .013 for MI; 1.23 [1.09-1.39], P = .001 for cardiac death/MI). CONCLUSIONS: Our novel segmentation method and corresponding MIS efficiently yield satisfactory prognostic information.