Abstract 24: Non-Obstructive Coronary Artery Disease Is Not Benign: Insights from the VA CART Program on the Association between Non-Obstructive Disease and Cardiac Events

Abstract

Introduction: The traditional focus of cardiac care on obstructive (>70% stenosis) CAD potentially distracts from the risks inherent in non-obstructive CAD. However, surprisingly little is known about non-obstructive CAD outcomes. Therefore, we determined the association between non-obstructive CAD and cardiovascular outcomes. Methods: Using the national VA CART program, we studied all veterans undergoing elective coronary angiography for angina between October 2007 and September 2012. Patients were categorized by CAD extent (none (no stenosis >20%), non-obstructive (no stenosis >=70%), obstructive (any stenosis >=70%)) and distribution (1, 2, or 3 vessel), and assessed for major adverse cardiac events (MACE), defined as all-cause mortality and MI. We adjusted for demographic, clinical, and treatment factors using Cox proportional hazards modeling. Secondary analyses sub-divided non-obstructive CAD into mild (20-49% stenosis) and moderate (50-69% stenosis) disease. Results: During the study period, 40,872 veterans underwent catheterization. Of these, 8411 (20.6%) had no CAD, 5219 (17.7%) had 1V non-obstructive CAD, 3034 (10.3%) had 2V non-obstructive CAD, 1388 (4.7%) had 3V non-obstructive CAD, 8588 (29.1%) had 1V obstructive, 5227 (17.7%) had 2V obstructive, and 6017 (20.4%) had 3V/LM obstructive CAD. MACE rates progressively increased with increasing CAD severity (Figure). This association persisted after risk adjustment (HR 1.28 (1.08, 1.51) for 1V non-obstructive, 1.29 (1.08, 1.52) 2V non-obstructive, 1.44 (1.12, 1.86) 3V non-obstructive, 1.93 (1.64, 2.28) 1V obstructive, 2.73 (2.28, 3.27) 2V obstructive, and 2.98 (2.52, 3.53) 3V/LM obstructive CAD)). A trend toward higher MACE in moderate 3V non-obstructive compared to 1V obstructive CAD (HR 1.34 (0.71, 2.52)) was noted. Conclusions: Non-obstructive CAD, relative to no CAD, is associated with 28-44% higher odds of MACE. MACE risk progressively increases by CAD extent, rather than abruptly increasing between non-obstructive and obstructive CAD. The risks of adverse events were similar for 3V non-obstructive CAD and 1V obstructive CAD, highlighting the limitations of a dichotomous characterization of angiographic CAD and a need to recognize the risks inherent in non-obstructive CAD.

Antiplatelet Therapy for Secondary Prevention After Myocardial Infarction in Antiplatelet-Naive High Cardiovascular Risk Patients with Non-Obstructive Coronary Artery Disease

“…[2][3][4][5] The vulnerability of the non-obstructive plaque with erosion and subsequent thrombosis is a major pathological substrate of NOCAD-associated MACEs. [6][7][8][9][10] Therefore, the relevance of antiplatelet therapy is high in patients with NOCAD. However, the effectiveness of different antiplatelet treatment regimens and secondary prevention strategies for patients with non-obstructive coronary artery disease is still uncertain.…”

Comparison of Long-term Preventive Effects of Dual Antiplatelet Therapy vs. Monotherapy in High Cardiovascular Risk Patients After Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA)

“…[5][6][7][8][9] Growing evidence indicates that nonobstructive coronary artery disease (NOCAD) is linked with a significant risk of future major adverse cardiovascular and cerebrovascular events (MACCEs), primarily due to nonobstructive plaque erosion and subsequent thrombosis. [10][11][12][13] Therefore, antiplatelet therapy becomes especially important in patients with NOCAD. However, the efficacy of various antiplatelet therapy regimens for preventing MACCEs in individuals with nonobstructive coronary artery disease remains unclear.…”