The effect of coronary revascularization on regional myocardial blood flow as assessed by stress positron emission tomography.

OBJECTIVES: We examined whether regional improvement in stress myocardial blood flow (sMBF) following angiography-guided coronary revascularization depends on the existence of a perfusion defect on positron emission tomography (PET). BACKGROUND: Percent stenosis on coronary angiography often is the main factor when deciding whether to perform revascularization, but it does not reliably relate to maximum sMBF. PET is a validated method of assessing sMBF. METHODS: 19 patients (79% M, 65 ± 12 years) underwent PET stress before and after revascularization (17 PCI, 2 CABG). Pre- and post-revascularization sMBF for each left ventricular quadrant (anterior, septal, lateral, and inferior) was stratified by the presence or absence of a baseline perfusion defect on PET and whether that region was revascularized. RESULTS: Intervention was performed on 40 of 76 quadrants. When a baseline perfusion defect existed in a region that was revascularized (n = 26), post-revascularization flow increased by 0.6 ± 0.7 cc/min/g (1.2 ± 0.4 vs 1.7 ± 0.8, P < 0.001). When no defect existed but revascularization was performed (n = 14), sMBF did not change significantly (1.7 ± 0.3 vs 1.5 ± 0.4 cc/min/g, P = 0.16). In regions without a defect that were not revascularized (n = 29), sMBF did not significantly change (2.0 ± 0.6 vs 1.9 ± 0.7, P = 0.7). CONCLUSIONS: When a stress-induced perfusion defect exists on PET, revascularization improves sMBF in that region. When there is no such defect, sMBF shows no net change, whether or not intervention is performed in that area. PET stress may be useful for identifying areas of myocardium that could benefit from revascularization, and also areas in which intervention is unlikely to yield improvement in myocardial blood flow.

Disparity between angiographic coronary lesion complexity and lipid core plaques assessed by near-infrared spectroscopy.

OBJECTIVE: The purpose of this study was to determine if there was a relationship between angiographic lesion complexity and the extent of lipid core plaque (LCP) identified by catheter-based near-infrared spectroscopy (NIRS). BACKGROUND: The angiographic complexity of coronary artery disease (CAD) is used to predict outcomes in patients undergoing percutaneous coronary intervention (PCI). The SYNTAX score, an angiographic tool quantifying the complexity of CAD, is associated with PCI outcomes. Recently, a novel catheter-based imaging technique using NIRS can identify LCP, which also is associated with PCI periprocedural myocardial infarction (MI). However, it is unknown whether these events are related to distinct adverse event prone pathobiology, such as a LCP within a complex angiographic lesion. Thus, we hypothesized that LCP identified by NIRS would be associated with high SYNTAX score. METHODS: Seventy-eight patients who underwent coronary angiography and target-vessel NIRS were selected from the Chemometric Observations of Lipid Core Containing Plaques of Interest in Native Coronary Arteries Registry, an industry sponsored registry to collate clinical findings in all patients undergoing NIRS evaluation. A lipid core burden index (LCBI) was obtained from the scan of the proximal 50 mm of the target vessel. Three vessel SYNTAX (total, tSYN) and target single vessel (only NIRS-interrogated vessel) SYNTAX (1vSYN) scores were calculated and compared to LCBI. High LCBI was defined as (>110) and was compared to tertile scores for 1vSYN score (low 0-5, intermediate 6-10, high ≥11) and previously established tertiles for tSYN score (low 0-22, intermediate 23-32, high ≥33). RESULTS: Patients had mean age of 63 years with prevalence of females (10%), diabetes mellitus (28%), hypertension (88%), and smoking history (72%); 1vSYN and tSYN scores correlated poorly with LCBI [(r(2) = 0.25; P = 0.02; n = 78) and (r(2) = 0.24; P = 0.04; n = 78), respectively]. Mean LCBI did not differ significantly across all tertiles of 1vSYN or tSYN scores. CONCLUSIONS: Angiographic SYNTAX score only weakly correlated with LCBI. It is of interest as well that high LCBI was also present in cases of low SYNTAX scores. The disparity between the degree of angiographic complexity and the amount of LCP supports postulated mechanisms of the adverse event propensity even in patients who demonstrate low angiographic complexity. Future studies are necessary to address the clinical significance of high LCBI in patients with low-to-intermediate angiographic complexity and their potential for PCI-related complications.

Coronary artery vasospasm and cardiogenic shock as the initial presentation for eosinophilic granulomatosis with polyangiitis.

A 68-year-old woman presented to our hospital with unstable angina and was admitted for further evaluation. While hospitalized, she developed persistent angina with hypotension along with ST-segment elevation in leads V1-V2 along with lead aVR elevation on 12-lead electrocardiogram. Coronary angiography revealed diffuse multi-vessel coronary vasospasm most notably in the left anterior descending artery (LAD). Due to incomplete resolution of vasospasm with intracoronary verapamil and nitroglycerin, along with hemodynamic compromise requiring an intra-aortic balloon pump, percutaneous coronary intervention (PCI) of the LAD was performed. Clinical workup revealed hypereosinophlia and elevated IgE; diagnosis of eosinophilic granulomatosis with polyangiitis was confirmed with evidence of radiographic migratory pulmonary infiltrates and airway obstruction on spirometry. The patient had recurrent angina after PCI but her symptoms resolved fully after a course of corticosteroids. We attribute her refractory vasospastic angina to previously undiagnosed small/medium-vessel vasculitis. .