Combined rest redistribution thallium-201 SPECT and low-dose dobutamine contractility assessment in a simple and practical new viability protocol.

OBJECTIVE: Rest-redistribution (RR) thallium-201 (Tl-201) imaging is commonly used for myocardial viability evaluation. Contractile reserve (CR) assessment with low-dose dobutamine (LDD) is another method that highly predicts functional recovery following revascularization. In this study, we investigate the feasibility of a new protocol that provides combined Tl-201 uptake, resting and CR functional regional myocardial information in a single examination. METHODS: A total of 41 patients underwent RR-gated-SPECT Tl-201 myocardial perfusion imaging. The LDD infusion was maintained during delayed imaging. Segmental Tl-201 uptake was classified into normal, fixed decrease (mild to absent) and reversible, and sub-classified by wall motion (WM)/thickening (WT) changes between early resting and delayed LDD gated images into normal, fixed or improved dysfunctional (CR present) segments. RESULTS: Out of 820 examined segments, 33 showed no appreciable Tl-201 uptake to evaluate WM/WT. In a dysfunctional myocardium, CR was significantly higher (P < 0.001) in reversible and fixed than in normal Tl-201 segments. The CR in dysfunctional segments with fixed decrease Tl-201 uptake was significantly higher (P < 0.05) in mild and moderate than in severe fixed defects. Both fixed Tl-201 defects and lack of CR were observed more (P < 0.05) in akinetic/dyskinetic than in hypokinetic segments. CONCLUSIONS: Simultaneous assessment of myocardial viability by RR Tl-201 uptake, resting and CR functional regional information is feasible and can be easily attained using this new protocol. Moreover, this protocol requires no additional time or radioactivity when compared with the usual RR Tl-201 protocol. Validation of this protocol with patients' revascularization data is needed.

Coronary artery bypass grafting and percutaneous coronary intervention in patients with end-stage renal disease.

OBJECTIVES: To determine the relative risks of long-term mortality between coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) among patients with end-stage renal disease (ESRD). METHODS: We identified 1015 patients with ESRD who underwent coronary revascularization between 1996 and 2008 within Kaiser Permanente Northern California. We obtained clinical variables from health plan databases, state death certificates and social security administration files. Our primary and secondary outcomes, respectively, were all-cause mortality and repeat revascularization. Our primary predictor was CABG compared with PCI. We used a Cox proportional hazards model for multivariable analyses. RESULTS: The mean age of CABG and PCI patients was similar (64.7 ± 10.6 and 63.4 ± 9.3, respectively, P = 0.06). The CABG group had a higher proportion of diabetics (P = 0.045), and higher nitrate use (P = 0.01). Adjusted for age, gender, race, year of index revascularization, number of vessels intervened, duration of dialysis and baseline comorbidities, patients referred for CABG during the first year had a hazard ratio (HR) of 1.16 [95% confidence interval (CI), 0.80-1.67] for mortality compared with PCI. During Years 1-5, the HR was 0.91 (95% CI, 0.63-1.33) with an overall HR of 0.73 (95% CI, 0.43-1.22). The sub-HR as calculated by the Fine-Gray competing risk model was 0.51 (95% CI, 0.31-0.85). CONCLUSIONS: As there are no randomized clinical trials in this area, our observational study adds to the growing body of literature that suggests a significant decrease in repeat revascularization with CABG and at least equivalency in long-term mortality with CABG when compared with PCI in ESRD patients.