• Richard C Brunken, Joseph K Perloff, Johannes Czernin, Roxana Campisi, Susan Purcell, Pamela D Miner, John S Child, and Heinrich R Schelbert.
• Dept. of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California, Los Angeles, USA. brunker@ccf.org
• Am. J. Physiol. Heart Circ. Physiol. 2005 Nov 1;289(5):H1798-806.

AbstractIn 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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