3-D quantitative coronary angiography reliably identifies occult severe lesions

LAS VEGAS — Surrogate 3-D quantitative coronary angiography, a technique incorporating results from two separate orthogonal angiographic views, can reliably identify severe lesions often undetected by conventional angiography, according to a late-breaking clinical trial presented at the Society for Cardiovascular Angiography and Interventions Scientific Sessions.

“Coronary angiography is typically done by full-speed, single-view analysis and, for several reasons, is fraught with difficulty in identifying blockages in diffusely diseased arteries,” Charles Laham, MD, FACC, FRCPC, FSCAI, interventional cardiologist at Holy Family Memorial Hospital in Manitowoc, Wis. and Midwest Cardiovascular Research Foundation associate, told Cardiology Today. “Through a series of sub-studies, the IQ-CATEGORIZE study has shown significant inaccuracy in this full-speed, single-view approach.”

Charles Laham

Researchers hypothesized that surrogate 3-D quantitative coronary angiography (3D-QCA), using both slow-speed film review and coronary catheter size as objective markers for severity, could mimic results obtained via intravascular ultrasound (IVUS). They predicted that mean minimum luminal diameter obtained from two separate orthogonal angiographic views, 35° to 90° apart, would accurately identify lesions through mathematical calculation of how high-grade potential hemodynamically severe disease would appear, based on prior flow wire-IVUS comparison studies.

This approach was evaluated in 131 indeterminate lesions in 79 patients. All lesions had moderate angiographic severity (defined as <70%) in two views, and included 29 lesions in vessels of small size (2.6-3 mm), 71 in medium- to large-sized vessels (3.1-4.5 mm), 18 in left main vessels and 13 in very large (>4.5 mm) non-left main vessels. All participants underwent both surrogate 3D-QCA and IVUS.

By 3D-QCA blockage assessment in 2.6-4.5 mm vessels, an average lumen less than 2 mm (the caliber of a 6F catheter) was highly predictive of severe blockage of >70% plaque area stenosis by IVUS (diagnostic accuracy: 93% for small vessels, 97% for medium-large vessels). Similarly, analysis of lesions located in very large or left main vessels indicated that an average lumen less than the 2.67 mm caliber of an 8F catheter was highly predictive of severe disease, defined as >67% plaque by IVUS severity criteria (accuracy: 94% for left main vessels, 92% for very large non-left main vessels).

IQ-CATEGORIZE researchers concluded that surrogate 3D-QCA, conducted via two-view orthogonal angiography, can reliably detect severe stenosis in occult suspicious lesions in both smaller, medium and larger vessels in all locations.

“These findings are likely to lead to more effective detection of clinically relevant blockages in those often overlooked by traditional angiographic criteria, and may support their further scrutiny in the appropriate clinical setting,” Laham said. – by Adam Taliercio

For more information:

Laham C. Late-breaking clinical trials. Presented at: the Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 28-31, 2014; Las Vegas.

Disclosure: Laham reports no relevant financial disclosures.