The effect of coronary artery plaque composition, morphology and burden on Absorb bioresorbable vascular scaffold expansion and eccentricity - A detailed analysis with optical coherence tomography.

AIMS: Suboptimal stent expansion correlates with adverse cardiac events. There is limited information regarding Absorb bioresorbable vascular scaffold (BVS) expansion characteristics. Optical coherence tomography (OCT) allows for high-resolution assessment of plaque morphology, composition and assessment of BVS expansion. This study evaluates coronary plaque composition, morphology and burden and their effect on Absorb BVS expansion using OCT. METHODS AND RESULTS: Two thousand three hundred and thirty four frames totalling 462.6 mm of BVS from twenty OCT-guided BVS implantations were examined. 200 µm longitudinal cross-sections of each BVS were analysed for lumen contours and plaque characteristics. The relationship between each plaque characteristic and scaffold expansion index (SEI) or scaffold eccentricity index (SEC) was analysed by repeated measures ANOVA. Forty-four fibrous and 265 calcific plaques were identified. Lower SEI was significantly (p<0.001) associated with greater calcific plaque (CP) area (mean SEI 78.9% vs. 80.0%), thickness (78.5% vs. 80.4%) and lower CP depth (78.3% vs. 80.2%). Lower SEC was significantly (p<0.001) associated with greater fibrous plaque (FP) area (0.84 vs. 0.85), thickness (0.83 vs. 0.86), arc angle (0.84 vs. 0.85), greater CP area (0.83 vs. 0.86), CP thickness (0.83 vs. 0.86), CP angle (0.84 vs. 0.85) and lower CP depth (0.84 vs. 0.85). Greater FP area was associated with greater SEI (81.0% vs. 80.0%, p<0.001), even after adjustment for target vessel size. Greater FP angle (80.7% vs 78.3%, p<0.001) and quadrants occupied were also associated (80.0% vs 78.5%, p<0.002) with greater SEI. CONCLUSION: BVS expansion and eccentricity are significantly impacted by plaque composition, morphology and burden.

Clinical utility of optical coherence tomography (OCT) in the optimisation of Absorb bioresorbable vascular scaffold deployment during percutaneous coronary intervention.

AIMS: The Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) represents an important advance in percutaneous coronary intervention (PCI) technology. With increasing use of BVS, it is important to understand its expansion characteristics to ensure optimal scaffold deployment. Optical coherence tomography (OCT) has been shown to improve detection of intraprocedural complications compared with conventional intravascular imaging modalities. This study aimed to determine whether or not OCT, post successful angiographic BVS implantation, influenced decision making with regard to the need for further scaffold optimisation. METHODS AND RESULTS: Consecutive patients undergoing OCT-guided BVS implantation from August 2012 to March 2013 were reviewed to determine if further intervention was required to optimise BVS implantation, based on OCT performed after what was deemed to be an optimal angiographic result. Nineteen patients with 29 scaffolds were analysed. Mean age was 53.7, with 84% male. There was a range of lesion types with 12 (63%) type A and seven (37%) type B or C. Of 29 scaffolds analysed, 28% required further intervention after OCT review, three (37.5%) due to scaffold malapposition and five (62.5%) due to scaffold underexpansion. CONCLUSIONS: Despite achieving angiographic success in all BVS implantations, further optimisation was required in over a quarter of patients on the basis of OCT findings.

Novel use of a guiding catheter to relieve left main stem occlusion complicating Stamford type A aortic dissection.

Acute ST elevation myocardial infarction occurring as a result of acute aortic dissection is a relatively rare complication with an incidence of 1-2%. However, despite this the outcome is frequently fatal. This report documents novel use of a percutaneous guiding catheter to relieve left main stem occlusion complicating Stamford type A aortic dissection, as a bridge to successful surgical treatment. A 62-year-old man presented with acute chest pain and electrocardiographic changes consistent with acute anterior myocardial infarction, and was sent for primary percutaneous coronary intervention. Angiography demonstrated an acute Stamford type A aortic dissection with associated secondary myocardial infarction caused by mechanical obstruction of the left main coronary artery by the dissection flap. Engagement of the coronary ostium with a guide catheter relieved the obstruction and allowed transfer of the patient to the operating theatre where surgery was successfully performed.

Differential effects of beta-adrenoreceptor antagonists on central and peripheral blood pressure at rest and during exercise.

BACKGROUND: Differential effects of beta-adrenoreceptor antagonists (beta-ARB) on central and peripheral blood pressure may relate to change in heart rate and/or vasodilator tone and thus be exaggerated during exercise. AIMS: To examine acute effects of selective and nonselective beta-ARB on central and peripheral blood pressure, cardiac output and peripheral vascular resistance during exercise. METHODS: Healthy volunteers (n= 20, 18 men, 19-54 years) received propranolol 80 mg, bisoprolol 20 mg, and placebo 1 h before bicycle ergometry (50, 75 and 100 W each for 3 min) in a randomized, cross-over study. Cardiac output was determined by pulmonary uptake of soluble and inert gas tracers (InnoCor, Innovision). Central systolic blood pressure (SBP) was determined from the late systolic shoulder of the digital artery pressure waveform (Finometer, Finopres). RESULTS: At rest, both beta-ARB reduced brachial but not central SBP (compared with placebo). During exercise, beta-ARB reduced brachial SBP (reductions of 19.9 +/- 4.3 mmHg and 23.2 +/- 2.7 mmHg for propranolol and bisoprolol, respectively, at 100 W, each P < 0.0001) but not central SBP. The difference between peripheral and central SBP was reduced, relative to that during placebo, by 21.5 mmHg (95% confidence interval 8.8, 34.1) and 26.4 mmHg (18.1, 34.8) for propranolol and bisoprolol, respectively, at 100 W (each P < 0.01). There was no significant effect of beta-ARB on diastolic blood pressure or peripheral vascular resistance. CONCLUSIONS: Despite reducing brachial blood pressure, acute beta-adrenoreceptor blockade in man at rest and during exercise does not reduce central blood pressure.