The right ventricle (RV) is hypertrophied at birth and in the neonatal period. The RV regresses to a normal phenotype in the first month of life correlated with a concomitant drop PVR over that time. The RV may remain hypertrophied and compensated in response to maintained afterload in patients with congenital heart disease (CHD) for decades; whereas the hypertrophied RV acquired in adulthood from pulmonary arterial hypertension (PAH) quickly transitions to failure, and remains their primary determinant of mortality in PAH. Potentially, the transition from RV compensation to failure has been attributed to ischemia from deficient capillary density from inadequate angiogenesis in RV hypertrophy. Angiogenesis is largely regulated by the transcription factor hypoxia-inducible factor 1a (HIF1a), which governs the transcription of proangiogenic signaling effectors. Two such effectors strongly promoting angiogenesis under HIF1a regulation are vascular endothelial growth factor (VEGF) and stromal derived factor 1 (SDF1), which promote endothelial cell survival/proliferation and recruitment of CXCR4+ stem cells, respectively. We hypothesized that sustained HIF1a-driven angiogenesis maintains adequate RV vascularity in hypertrophy, thus preventing the transition from RV compensation to failure in CHD patients. The free walls of neonatal rat RVs had elevated levels of HIF1a (immunoblot and nuclear localization) compared to those of adult RVs, adult LVs, and neonatal LVs. This was associated with increased VEGF and SDF1 expression (Immunoblot and ELISA), which correlated with increased angiogenesis (matrigel assay) and CXCR4+ stem cell recruitment (Boyden chamber migration assay). Neonatal RVs had elevated expression vascular density (CD31 expression) and tissue perfusion (Lectin) compared to adult RVs, further supporting proangiogenic signaling. Human compensated RV hypertrophy myocardium from CHD patients had elevated SDF1 and CXCR4 expression compared to normal adult RV and LV myocardium (immunoblot), suggesting HIF1a driven angiogenic pathways are maintained in CHD tissues. Therapies that maintain HIF1a signaling may delay the transition from compensation to failure in adults with acquired PAH.
Common bile duct (CBD) stones are extracted with a basket or balloon during ERCP with sphincterotomy. However, some stones are difficult to extract by conventional means. Cholangioscopy with lithotripsy is a modality to treat these difficult stones. We describe the clinical efficacy of single-operator per oral cholangioscopy (SOPOC) for difficult stones and discuss cost savings by avoiding surgical intervention.Retrospective chart review was performed for all patients referred for difficult CBD stones. Clinical success was defined as clearing the duct of all stones. The cost of cholangioscopy (in $CDN) was calculated by adding all costs associated with the procedure(s), surgery, hospital stay or treatment of adverse events. This cost was compared with the projected cost of surgical bile duct exploration.A total of 51 patients (35 female) with a mean age of 66 years underwent 58 SOPOC procedures. Median procedure time was 67 minutes (95% CI, 61.5-73.5). The CBD was successfully cleared in 47 of 51 patients (93%). Minor adverse events were seen in seven patients (14%). The actual average per procedure cost was $4555±$2647. This compares with a projected cost of $7766 and $6175 for open and laparoscopic bile duct exploration, with a cost-per-case saving of $3210 and $1619, respectively.SOPOC with lithotripsy is highly effective and safe for the treatment of difficult common bile duct stones. In addition, significant cost savings may be realized by avoiding surgical bile duct exploration.
Hearts donated following circulatory death (DCD) may represent an additional source of organs for transplantation; however, the impact of donor extubation on the DCD heart has not been well characterized. We sought to describe the physiologic changes that occur following withdrawal of life-sustaining therapy (WLST) in a porcine model of DCD. Physiologic changes were monitored continuously for 20 min following WLST. Ventricular pressure, volume, and function were recorded using a conductance catheter placed into the right (N = 8) and left (N = 8) ventricles, and using magnetic resonance imaging (MRI, N = 3). Hypoxic pulmonary vasoconstriction occurred following WLST, and was associated with distension of the right ventricle (RV) and reduced cardiac output. A 120-fold increase in epinephrine was subsequently observed that produced a transient hyperdynamic phase; however, progressive RV distension developed during this time. Circulatory arrest occurred 7.6±0.3 min following WLST, at which time MRI demonstrated an 18±7% increase in RV volume and a 12±9% decrease in left ventricular volume compared to baseline. We conclude that hypoxic pulmonary vasoconstriction and a profound catecholamine surge occur following WLST that result in distension of the RV. These changes have important implications on the resuscitation, preservation, and evaluation of DCD hearts prior to transplantation.
