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Biomedical subjects

V Falk

Publications and source records attributed to V Falk.

144 records · Page 8Linked to original sources

Experimental aortic stenosis and corresponding left ventricular hypertrophy in sheep.

Left ventricular hypertrophy (LVH) is an independent cardiac risk factor. A simple standard experimental model of inducing LVH for further studies using experimental aortic stenosis in sheep was performed. The aim of this study is to describe animal-specific requirements as well as perioperative therapy, postoperative care, and the use of echocardiography for routine follow-up examinations. Supracoronary aortic banding was performed in 55 female sheep at an age of 6 to 8 months. General anesthesia and an antero-lateral thoracotomy were used. The objective was to achieve pressure gradients of 20 to 30 mm Hg. In addition a 4th intercostal space rib window was created to improve echocardiographic vision. The operations were completed successfully in all animals. Intraoperatively, little severe arrhythmia occurred. During the follow-up interval of 8 +/- 1.3 months, 8 animals died, due to incomplete perforation of the ascending aorta (3), chronic heart failure (2), pericardial cyst (1), and respiratory failure and infection (2). All remaining animals were amenable for further studies. Severe LVH was diagnosed with routine echocardiography on follow-up. Thus, experimental aortic stenosis in sheep is a safe and relatively simple technique to generate stable LVH. Echocardiography is an easy tool for follow-up evaluations. Due to low complication rates, the sheep model is well suited for further research in LVH.

Animals↗

Ruptured giant syphilitic aneurysm of the descending aorta in an octogenarian.

Syphilis can lead to saccular aneurysms of the thoracic aorta. Today syphilitic aortic aneurysms are rare. The average time from primary infections to the development of aortic aneurysms is 10 to 15 years. An 83-year-old man was admitted with a giant aneurysm of the descending thoracic aorta. The patient had first experienced subacute pain in the left hemithorax some weeks previously. Computer tomography scan detected an 11 x 11 cm aneurysm of the descending aorta. Serodiagnostic tests for syphilis were highly positive. Femoro-femoral bypass was initiated and a tube graft was interposed. The postoperative course was uneventful, the patient was discharged at the twentieth postoperative day. Histological examination of the aneurysmal wall showed typical syphilitic changes. Postoperatively, Penicillin G was given for 6 months. Three years later the patient remains asymptomatic. Although extremely rare today, tertiary syphilis should be considered in the differential diagnosis of thoracic aneurysms. In selected octogenarians replacement of the descending aorta is possible.

Aged↗

Repair of coarctation of the aorta in neonates and young infants.

In repair of coarctation in neonates or young infants, inadequate removal of ductal tissue, failure to address hypoplasia of the aortic arch, and suture line tension have been reported to be important factors of residual or early recurrent stenosis at the coarctation repair site. In a consecutive series of neonates and young infants with coarctation, who were all operated without delay with extended resection, the clinical outcome regarding the development of restenosis and hypertension was studied. In addition, the resected specimens were investigated regarding the completeness of resection of ductal tissue. Twenty-five consecutive neonates and young infants (median age 22 days, range 5 to 39 days) who underwent surgical correction of coarctation were reviewed; the resected specimens were examined histologically to document the extent of ductal tissue in the aortic wall. Fifteen patients had a preductal coarctation with associated cardiovascular anomalies including a hypoplastic aortic arch (n = 11). The remaining 10 patients had a paraductal coarctation without associated intracardiac anomalies. In all patients, the isthmus was bypassed and an end-to-side anastomosis was constructed between the descending aorta and the undersurface of the proximal aortic arch (n = 13) or the distal ascending aorta (n = 12). In 13 patients without marked hypoplasia of the aortic arch, the coarctation repair was performed through a left thoracotomy. In the remaining 12 patients, the coarctation was repaired through a median sternotomy with CPB and hypothermic circulatory arrest, on the basis of an associated hypoplastic aortic arch (n = 4), hypoplastic aortic arch with intracardiac anomalies (n = 7), or a "bovine" innominate artery (n = 1). There was no perioperative or late mortality. At a median follow-up of 15 months, 1 patient (4%) developed a recurrent stenosis at the coarctation repair site; in the remaining 24 patients, echocardiography showed a widely patent anastomosis with no evidence of a hemodynamically significant gradient. None of the patients had hypertension. Histologic examination of the resected specimens demonstrated the presence of ductal tissue in the descending aorta with maximal extension into its lateral wall (mean 5.2 mm). In all specimens of the paraductal subtype, there was also extension of ductal tissue into the lateral wall of tbe isthmus (mean 3.9 mm). We conclude that: (1) in the absence of marked hypoplasia of the proximal aortic arch, coarctation can be repaired with low mortality and morbidity via a left thoracotomy; (2) in the presence of marked hypoplasia of the proximal aortic arch and/or if associated intracardiac defects also need to be repaired, we advocate repair of the coarctation and associated defects through a median sternotomy with circulatory arrest; (3) in view of the absence of postoperative hypertension in this series, early repair of aortic coarctation is recommended; and (4) because ductal tissue may extend not only into the descending aorta but also into the isthmus, complete excision of the coarctation and bypass of the isthmus are valuable techniques to avoid secondary constriction of the aorta by ductal tissue.

Aorta↗

The Leipzig experience with robotic valve surgery.

OBJECTIVES: The study describes the single-center experience using robot-assisted videoscopic mitral valve surgery and the early results with a remote telemanipulator-assisted approach for mitral valve repair. MATERIAL AND METHODS: Out of a series of 230 patients who underwent minimally invasive mitral valve surgery, in 167 patients surgery was performed with the use of robotic assistance. A voice-controlled robotic arm was used for videoscopic guidance in 152 cases. Most recently, a computer-enhanced telemanipulator was used in 15 patients to perform the operation remotely. RESULTS: The mitral valve was repaired in 117 and replaced in all other patients. The voice-controlled robotic arm (AESOP 3000) facilitated videoscopic-assisted mitral valve surgery. The procedure was completed without the need for an additional assistant as "solo surgery." Additional procedures like radiofrequency ablation and tricuspid valve repair were performed in 21 and 4 patients, respectively. Duration of bypass and clamp time was comparable to conventional procedures (107 A 34 and 50 A 16 min, respectively). Hospital mortality was 1.2%. Using the da Vinci telemanipulation system, remote mitral valve repair was successfully performed in 13 of 15 patients. CONCLUSION: Robotic-assisted less invasive mitral valve surgery has evolved to a reliable technique with reproducible results for primary operations and for reoperations. Robotic assistance has enabled a solo surgery approach. The combination with radiofrequency ablation (Mini Maze) in patients with chronic atrial fibrillation has proven to be beneficial. The use of telemanipulation systems for remote mitral valve surgery is promising, but a number of problems have to be solved before the introduction of a closed chest mitral valve procedure.

Adult↗

Minimally invasive approach for redo mitral valve surgery: a true benefit for the patient.

OBJECTIVES: Redo mitral valve surgery via sternotomy is associated with a substantial morbidity and mortality. This study evaluated a minimally invasive technique for mitral valve redo procedures. MATERIAL AND METHODS: Out of a series of 394 patients undergoing mitral valve repair or replacement via a right minithoracotomy, 39 patients underwent redo mitral valve surgery (59+/-13 years, 23 female). Previous cardiac surgeries included 17 patients with mitral valve repair, 6 patients with mitral valve replacement, 3 patients with aortic valve replacement, 2 patients with atrial septal defect closure, and 11 patients with coronary artery bypass grafting (CABG). In all cases, femoro-femoral cannulation was performed. The port access technique was applied in patients undergoing redo valve surgery. In patients with prior CABG, the operation was performed using deep hypothermia and ventricular fibrillation. RESULTS: In all cases, sternotomy was avoided. The mitral valve was replaced in 20 patients and repaired in 19. Time of surgery and cross-clamp time were comparable with the overall series (168+/-73 [redo] vs 168+/-58 min and 52+/-21 [redo] vs 58+/-25 min). Mortality was 5.1%. One patient had transient hemiplegia due to the migration of the endoclamp. All other patients had uneventful outcomes and normal mitral valve function at 3-month's follow-up. CONCLUSION: Redo mitral valve surgery can be performed safely using a minimally invasive approach in patients with a previous sternotomy. The right lateral minithoracotomy offers excellent exposure. It minimizes the need for cardiac dissection, and thus, the risk for injury. Avoiding a resternotomy increases patient comfort of redo mitral valve surgery.

Adult↗