Key result
Adults with cyanotic congenital heart disease had higher basal left ventricular myocardial perfusion compared to healthy controls (0.77 vs. 0.55 ml/min/g, P<0.02), with similar hyperemic perfusion.
Why the study?
Does myocardial perfusion reserve differ between adults with cyanotic congenital heart disease and healthy controls?
Case-Control (n=24)
Does myocardial perfusion reserve differ between adults with cyanotic congenital heart disease and healthy controls?
Absolute Event Rate: 0.77% vs 0.55%
p-value: p=<0.02
Adults with cyanotic congenital heart disease appear to undergo coronary circulation remodeling that preserves hyperemic myocardial perfusion despite chronic hypoxemia and erythrocytosis.
Supports adaptive perfusion remodeling in cyanotic CHD; hypothesis-generating for outcomes in larger prospective cohorts.
In patients with cyanotic congenital heart disease (CCHD), a right-to-left shunt results in systemic hypoxemia. Systemic hypoxemia incites a compensatory erythrocytosis, which increases whole blood viscosity. We considered that these changes might adversely influence myocardial perfusion in CCHD patients. Basal and hyperemic (intravenous dipyridamole) perfusion measurements were obtained with [13N]ammonia positron emission tomographic imaging in left (LV) and right (RV) ventricular and septal myocardium in 14 adults with CCHD [age: 34.1 yr (SD 6.5)]; hematocrit: 62.2% (SD 4.8)] and 10 healthy controls [age: 34.1 yr (SD 6.5)]. In patients, basal perfusion measurements were higher in LV [0.77 (SD 0.24) vs. 0.55 ml x min(-1) x g(-1) (SD 0.09), P < 0.02], septum [0.71 (SD 0.16) vs. 0.49 ml x min(-1) x g(-1) (SD 0.09), P < 0.001], and RV [0.77 (SD 0.30) vs. 0.38 ml x min(-1) x g(-1) (SD 0.09), P < 0.001]. However, basal measurements normalized for the rate-pressure product were similar to those of controls. Calculated oxygen delivery relative to rate-pressure product was higher in the patients [2.2 (SD 0.8) vs. 1.6 (SD 0.4) x 10(-5) ml O2 x min(-1) x g tissue(-1) x (beats x mmHg)(-1) in the LV, P < 0.05, and 2.0 (SD 0.7) vs. 1.4 (SD 0.3) x 10(-5) ml O2 x min(-1) x g tissue(-1) x (beats x mmHg)(-1) in the septum, P < 0.01]. Hyperemic perfusion measurements in CCHD patients did not differ from controls [LV, 1.67 (SD 0.60) vs. 1.95 ml x min(-1) x g(-1) (SD 0.46); septum, 1.44 (SD 0.56) vs. 1.98 ml x min(-1) x g(-1) (SD 0.69); RV, 1.56 (SD 0.56) vs. 1.65 ml x min(-1) x g(-1) (SD 0.64), P = not significant], and coronary vascular resistances were comparable [LV, 55 (SD 25) vs. 48 mmHg x ml(-1) x g x min (SD 16); septum, 67 (SD 35) vs. 50 mmHg x ml(-1) x g x min (SD 21); RV, 59 (SD 26) vs. 61 mmHg x ml(-1) x g x min (SD 27), P = not significant]. These findings suggest that adult CCHD patients have remodeling of the coronary circulation to compensate for the rheologic changes attending chronic hypoxemia.
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Brunken et al. (2005) conducted a case-control in Cyanotic congenital heart disease (n=24). Cyanotic congenital heart disease vs. Healthy controls was evaluated on Basal myocardial perfusion in the left ventricle (ml/min/g) (p=<0.02). Adults with cyanotic congenital heart disease had higher basal left ventricular myocardial perfusion compared to healthy controls (0.77 vs. 0.55 ml/min/g, P<0.02), with similar hyperemic perfusion.
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