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Biomedical subjects

Christian Schlensak

Publications and source records attributed to Christian Schlensak.

6 recordsLinked to original sources
PubMed2006

Aortic atresia with aortico-left ventricular tunnel mimicking severe aortic incompetence in utero.

A fetus was diagnosed with regurgitation from the aorta into the left ventricle. A large aortico-left ventricular tunnel with aortic atresia was identified postnatally by echocardiography in a neonate suffering from severe heart failure. We successfully reconstructed the valve and closed the tunnel with a patch on his first day of life. At three-month follow-up, the baby is asymptomatic with mild aortic regurgitation. The combination of congenital aortico-left ventricular tunnel and aortic atresia can be misinterpreted in prenatal echocardiography as aortic regurgitation. This pathology may require urgent operative interventions.

Aortic Valve↗
PubMed2005

Controlled reperfusion using a simplified perfusion system preserves function after acute and persistent limb ischemia: a preliminary study.

OBJECTIVE: Reperfusion of the limb after acute and persistent ischemia is associated with high rates of morbidity and mortality despite complete revascularization. Although reperfusion is a prerequisite for maintaining limb function, it may in itself cause further injury. There is experimental evidence that modification of the initial reperfusion modalities can minimize this reperfusion injury. We hypothesized that controlled reperfusion using a simple blood bag perfusion system reduces reperfusion injury and facilitates the return of normal function. METHODS: Fifteen consecutive patients (mean age, 80.5 +/- 5.0 years) with severe, acute lower-limb ischemia were allocated to two treatment arms in this prospective, controlled observational study. Group I (n = 8) underwent surgical embolectomy alone, and group II (n = 7) underwent surgical embolectomy plus controlled reperfusion using a simplified perfusion system. Indication for controlled reperfusion was made by the responsible surgeon. Controlled reperfusion consisted of a 30-minute infusion of a crystalloid reperfusion solution that was mixed with oxygenated blood (the blood:reperfusion solution ratio was 6:1) distal to the occlusion. Duration of ischemia, postoperative amputation rate, motor function of the ischemic limb, and pre- and postoperative serum creatine kinase levels were assessed. RESULTS: The duration of ischemia was 10.7 +/- 1.1 hours in group I and 19 +/- 5.2 hours in group II (P < .05). The site of the arterial occlusion was the iliac artery in nine patients and the common femoral artery in six patients. Full recovery was achieved in six of seven patients in group II and in only two of eight patients in group I (P < .05). There were three in-hospital deaths in group I, and two patients underwent major amputations. No in-hospital deaths or major amputations occurred in group II. CONCLUSION: The results from this preliminary study strongly suggest the hypothesis that the results of conventional embolectomy for acute, severe lower-limb ischemia can be improved by controlled reperfusion. To prove our preliminary findings, a large randomized, prospective, controlled, multicenter trial, the Controlled Reperfusion of the Acutely Ischemic Limb trial (CRAIL-Trial) is currently being conducted to prove our preliminary findings.

Acute Disease↗
PubMed2003

Cardioplegia in pediatric cardiac surgery: do we believe in magic?

Cardioplegia has become the gold standard of myocardial protection for practically every type of heart surgery during which the ascending aorta must be clamped. Although there is little doubt about the efficacy of cardioplegia in the adult heart, there are few studies on the pediatric heart and their results are contradictory. The physiology of pediatric heart muscle differs considerably from that of the adult myocardium. The pediatric heart distinguishes itself from that of the adult most impressively in its greater tolerance for ischemia. This ischemia tolerance is enhanced by the use of hypothermia. Considering that hypothermia is a powerful tool to prolong ischemia tolerance and that most pediatric cardiac surgeons report similar results using different types of cardioplegia, some surgeons are tempted to suspect that the contribution of the cardioplegia composition to protecting the pediatric heart may be overestimated. This provocative statement is critically discussed in this article. We examine the protective potential of cardioplegia (in various compositions), or of hypothermia, or of both in pediatric cardiac surgery. We pay special attention to several key differences between the physiologies of the pediatric myocardium and the adult myocardium and attempt to relate them to the available surgical methods of myocardial protection. We conclude that the composition of cardioplegia indeed is an important component of successful operative management in pediatric heart surgery. We provide evidence that the benefit of cardioplegia over hypothermia alone is minor at low temperatures (below 15 degrees C), but becomes substantial when the temperature increases.

Cardiac Surgical Procedures↗
PubMed2002

Cardiopulmonary bypass: Evidence or experience based?

OBJECTIVE: Evidence-based medicine is emerging as a new paradigm for medical practice. The purpose of this study was to evaluate the amount and quality of scientific evidence supporting principles that are currently applied for cardiopulmonary bypass performance. METHODS: A survey of all German departments of cardiac surgery regarding cardiopulmonary bypass performance disclosed major differences. Consequently, for 48 major principles of cardiopulmonary bypass performance, relevant Medical Subject Headings were identified, and a literature search of the Medline database was performed. Two sequentially applied sets of inclusion-exclusion criteria were selected to assess the best available evidence. RESULTS: Thirty-three thousand articles relating to the subject were identified. Among these, 1500 fulfilled the first set of inclusion criteria: meta-analysis of (randomized) controlled clinical trials and in vitro and animal studies. Rigorous methodological criteria were then applied to further select remaining publications. Ultimately, 225 articles referring to major cardiopulmonary bypass principles were identified as providing the best available evidence. These were graded according to their methodological rigor (susceptibility to bias). The scientific evidence on the investigated cardiopulmonary bypass principles did not prove to be of a high enough level to allow general recommendations to be made. CONCLUSIONS: The scientific data concerning the effectiveness and safety of key principles of cardiopulmonary bypass are insufficient in both amount and quality of scientific evidence to serve as a basis for practical, evidence-based guidelines.

Acid-Base Equilibrium↗
PubMed2002

Cardiopulmonary bypass reduction of bronchial blood flow: a potential mechanism for lung injury in a neonatal pig model.

BACKGROUND: During total cardiopulmonary bypass, blood flow to the lungs is limited to flow through the bronchial arteries. We tested the hypothesis that bronchial blood flow during cardiopulmonary bypass is insufficient to prevent ischemia of the lung and that perfusion of the pulmonary arteries with oxygenated blood during bypass would reduce lung injury. METHODS: Eighteen piglets (5.0 +/- 0.5 kg) were subjected to 120 minutes of normothermic total cardiopulmonary bypass, followed by 60 minutes of postbypass perfusion. Nine of them received continuous pulmonary perfusion with oxygenated blood during bypass. Six additional piglets served as a control group and were mechanically ventilated after sternotomy for 180 minutes only. We quantitated bronchial arterial blood flow, tissue lactate content, and alveolar septal thickness and surface area. We also obtained bronchioalveolar lavage fluid samples. RESULTS: With the beginning of cardiopulmonary bypass, bronchial arterial blood flow decreased to 13% of baseline (42.1 +/- 10.4 to 5.6 +/- 1.0 mL/min). It remained decreased until the end of bypass and returned to starting levels 60 minutes after bypass. The decrease in bronchial blood flow was associated with a 3-fold increase in tissue lactate content. At the end of reperfusion there was a 2-fold increase in alveolar septal thickness and significant accumulations relative to control in the bronchoalveolar lavage fluid of albumin, lactate dehydrogenase, neutrophils, and elastase. Controlled pulmonary perfusion significantly ameliorated all the observed changes. CONCLUSION: Cardiopulmonary bypass caused a reduction in bronchial arterial blood flow, which was associated with injury of the lung. Controlled pulmonary perfusion reduced injury to the lung during bypass. The inflammatory response, as evidenced by bronchoalveolar lavage fluid, may be caused by ischemia.

Animals↗