Parturients with hypertrophic cardiomyopathy: case series and review of pregnancy outcomes and anesthetic management of labor and delivery.

BACKGROUND: Advances in understanding the pathogenesis, diagnosis and management of hypertrophic cardiomyopathy have resulted in increased longevity and a better quality of life of affected patients considering pregnancy. Several case series which focused predominantly on obstetric details have reported generally good outcomes. However, there remains a paucity of data on the specifics of obstetric anesthesia in women with hypertrophic cardiomyopathy. METHODS: After Institutional Review Board approval, we reviewed antepartum transthoracic echocardiograms, cardiology, obstetric, anesthetic, and nursing labor records with a focus on anesthesia for labor and delivery and early postpartum complications in patients with hypertrophic cardiomyopathy who delivered between January 1993 and December 2013. RESULTS: There were 23 completed pregnancies in 14 patients: 12 parturients (52%) delivered vaginally, of whom seven (30%) required assistance (forceps, vacuum), and 11 (48%) had a cesarean delivery. In 17 cases (74%) delivery was uneventful, but six patients (26%) had complications including congestive heart failure (n=3) and postpartum hemorrhage (n=3). All patients had neuraxial labor anesthesia/analgesia, and none received general anesthesia. No hemodynamic instability or fetal distress directly related to anesthesia was documented. CONCLUSION: The database search of approximately 160000 deliveries over 20 years revealed only a small number of hypertrophic cardiomyopathy patients with completed pregnancies. No maternal or neonatal deaths were documented. Overall morbidity rate was 26% with a 13% incidence of peripartum congestive heart failure. In patients with mild to moderate disease, neuraxial anesthesia was safe, effective and well tolerated with no hemodynamic instability related to administration of local anesthetics.

Membrane fusion of erythrocytes as a model study of the effects of muscle relaxants on presynaptic exocytosis.

The exact mechanism by which synaptic vesicles fuse with the presynaptic nerve terminal membrane has not been determined. We therefore investigated the effects of muscle relaxants on membrane fusion using the human red blood cell as a model membrane. The kinetics of calcium-phosphate-induced membrane fusion were monitored continuously by noting the relief of fluorescence self-quenching of octadecyl-rhodamine B chloride (R18)-labeled and unlabeled membranes. The nondepolarizing muscle relaxants, vecuronium and pancuronium, inhibited membrane fusion of ghosts, inside-out vesicles (IOVs), and phosphatidylserine (PS)-loaded IOVs, whereas succinylcholine did not affect membrane fusion. The inhibitory effect of nondepolarizing muscle relaxants on membrane fusion suggests the prejunctional involvement of nondepolarizing muscle relaxants.