Renin secretion in the chronically perfused pulseless calf. Evidence for failure of stimulation by decreased pulse pressure

Risk factors of gastrointestinal bleeding after cardiopulmonary bypass in children: a retrospective study

Background

During cardiac surgery that involved cardiopulmonary bypass (CPB) procedure, gastrointestinal (GI) system was known to be vulnerable to complications such as GI bleeding. Our study aimed to determine the incidence and risk factors associated with GI bleeding in children who received CPB as part of cardiac surgery.

Methods

This retrospective study enrolled patients aged <18 years who underwent cardiac surgery with CPB from 2013 to 2019 at Shanghai Children's Medical Center. The primary outcome was the incidence of postoperative GI bleeding in children, and the associated risk factors with postoperative GI bleeding episodes were evaluated.

Results

A total of 21,893 children who underwent cardiac surgery with CPB from 2013 to 2019 were included in this study. For age distribution, 636 (2.9%) were neonates, 10,984 (50.2%) were infants, and 10,273 (46.9%) were children. Among the 410 (1.9%) patients with GI bleeding, 345 (84.2%) survived to hospital discharge. Incidence of GI bleeding in neonates, infants and children were 22.6% (144/636), 2.0% (217/10,984) and 0.5% (49/10,273), respectively. The neonates (22.6%) group was associated with highest risk of GI bleeding. Patients with GI bleeding showed longer length of hospital stays (25.8 ± 15.9 vs. 12.5 ± 8.9, P < 0.001) and higher mortality (15.9% vs. 1.8%, P < 0.001). Multivariate logistic regression analysis showed that age, weight, complicated surgery, operation time, use of extracorporeal membrane oxygenation (ECMO), low cardiac output syndrome (LCOS), hepatic injury, artery lactate level, and postoperative platelet counts were significantly associated with increased risk of GI bleeding in children with congenital heart disease (CHD) pediatric patients that underwent CPB procedure during cardiac surgery.

Conclusion

The study results suggest that young age, low weight, long operation time, complicated surgery, use of ECMO, LCOS, hepatic injury, high arterial lactate level, and low postoperative platelet counts are independently associated with GI bleeding after CPB in children.

Takayasu's Arteriopathy with Associated Descending Thoracic Aortic Dissection During Pregnancy: A Multidisciplinary Approach Leading to a Successful Outcome: A Case Presentation

Takayasu's arteriopathy is a rare arterial inflammatory disease of unknown etiology that commonly affects the aorta, its major branches, and the pulmo nary artery. Although this process most often causes narrowing and occlusion of the vessels involved, it is associated only rarely with aneurysm formation or dissection of the vessel. Although there are sporadic reports of pregnancy in conjunction with Takayasu's arteriopathy, the combination of this disorder with pregnancy and an aortic dissection is very unusual.

This case report and literature review details the clinical management of a gravid female with clinical problems that were managed through close coopera tion among cardiothoracic surgery, anesthesia, obstetrics and gynecology, and perinatology units. This multidisciplinary approach led to the successful opera tive repair of a descending thoracic aortic dissection in a pregnant woman with Takayasu's arteriopathy who later delivered a normal full-term infant.

Influence of pulsatile perfusion upon renin release from the isolated perfused rat kidney

It is well established that renin release from the juxtaglomerular epithelioid cells in the media of the afferent arteriole strongly depends on the mean renal perfusion pressure, whereas a possible influence of the pulsation of blood pressure on renin release has only occasionally been investigated, and the results are contradictory. Such an influence on renin release cannot be excluded because pulsation is known to modulate arterial baroreceptors and vascular tone in some resistance vessels. In the isolated perfused rat kidney, we found a pulsation amplitude-dependent inhibition of renin release that could be blocked either by vasodilatation or by calcium channel blockade. The inhibition occurred at perfusion pressures between 85 and 125 mm Hg. The underlying pulsation pressure-sensitive mechanism has to be ascribed integrating properties, because a constant-flow pressure rise to the "systolic" value of pulsatile perfusion resulted in virtually the same inhibition of renin release. Moreover, a reduced urine flow during pulsatile perfusion provides evidence for preglomerular constriction under these conditions. It is concluded that, besides pathological changes of renal perfusion pressure, variations of the pulse amplitudes, e.g. resulting from renal artery stenosis or atherosclerosis, may also influence renin release and contribute to renovascular hypertension.