Michael Gorlitzer

Long-term experience in autologous in vitro endothelialization of infrainguinal ePTFE grafts

OBJECTIVE Based on a previous randomized study showing significantly superior patency rates for in vitro endothelialized expanded polytetrafluoroethylene (ePTFE) grafts we investigated whether it was feasible for a nontertiary institution to offer autologous in vitro endothelialization to all elective infrainguinal bypass patients who had no suitable saphenous vein available. METHODS Over a period of 15 years, 310 out of 318 consecutive nonacute patients (age 64.7 +/- 8.6) received 341 endothelialized ePTFE grafts (308 femoropopliteal: 153 above knee [AK] and 155 below knee [BK] and 33 femorodistal). Autologous endothelial cells were harvested from short segments (3.9 +/- 1.1 cm) of subcutaneous veins (80% cephalic, 11% basilic, 2% external jugular, and 7% saphenous) and grown to mass cultures within 18.9 +/- 4.5 days before being confluently lined onto fibrin glue-coated ePTFE grafts. The graft diameter was 6 mm (64%) or 7 mm (36%). The overall procedure-related delay for graft implantation was 27.6 + 7.8 days. Growth failure prevented 2.5% of patients from receiving an endothelialized graft. The mean observation period was 9.6 years. Primary patencies were obtained from Kaplan-Meier survivorship functions. Explants for morphological analysis were obtained from eight patients. RESULTS The overall primary patency rate of femoropopliteal grafts was 69% at 5 years (68% [AK] vs 71% [BK]) and 61% at 10 years (59% [AK] vs 64% [BK]). Primary patency of 7 mm vs 6 mm grafts was 78%/62% at 5 years and 71%/55% at 10 years. The difference between the two groups was statistically significant (log rank test P = .023; Breslow test P = .017). Stage I vs II/III patients showed 5-year patencies of 67% vs 73% (N.S.) and 10-year patencies of 61%% vs 53% (N.S.). The primary patency of femorodistal grafts was 52% at 5 years and 36% at 10 years. The limb salvage rate was 94% (fempop) vs 86% (femdistal) at 5 years and 89% vs 71% at 10 years. All retrieved samples showed the presence of an endothelium after 38.9 +/- 17.8 months. CONCLUSION Autologous in vitro endothelialization was shown to be a feasible routine procedure at a nontertiary hospital. Explants confirmed the presence of an endothelium years after implantation while the primary patency in the particularly challenging subgroup of patients without a suitable saphenous vein resembles that of vein grafts.

Multicenter early experience with extended aortic repair in acute aortic dissection: Is simultaneous descending stent grafting justified?

OBJECTIVE In acute type A aortic dissection, the extension of repair to downstream aorta has been controversially discussed. We present the early results of a multicenter study using a hybrid stent graft prosthesis. METHODS Between January 2005 and January 2010, the data from 191 patients after combined proximal aortic replacement and antegrade stent grafting were collected in the database of the International E-vita open Registry. Of the 191 patients, 68 underwent surgery for acute aortic dissection and were included in the present study. Hypothermic circulatory arrest and selective cerebral perfusion were routinely used. Computed aortic imaging was performed for false lumen evaluation during follow-up. RESULTS The in-hospital mortality rate was 13% (9/68). Along the stent graft, the rate of immediate complete false lumen thrombosis was 86% (51/59) and increased during follow-up (23 ± 17 months) to 94% (46/49). Distally, complete or partial false lumen thrombosis was initially observed in 61% (36/59) and in 82% (40/49) after follow-up. The 1- and 3-year actuarial survival rate was 82% and 74%, respectively. CONCLUSIONS Extended thoracic aortic repair of acute aortic dissection with a hybrid stent graft is feasible at acceptable early mortality and promotes false lumen thrombosis around the stent graft and below.

Arch replacement and downstream stent grafting in complex aortic dissection: first results of an international registry.

OBJECTIVES Arch replacement combined with antegrade stent grafting of the descending aorta represents a hybrid surgical approach for extensive thoracic aortic disease. This multicentre study evaluates the early results of this method in complex aortic dissection (AD). METHODS Retrospective data acquisition was achieved by institution of an international registry. A hybrid stent graft with integrated vascular prosthesis for arch replacement (E-vita open®) was used. From January 2005 to March 2009, 106 patients (mean age 57; 77% male) with complex AD (55 acute, 51 chronic) were studied. RESULTS As many as 49/106 (46%) patients underwent emergency surgery. Stent-graft deployment and arch replacement (95 total, 11 subtotal) were performed under hypothermic circulatory arrest (HCA (8±6min) and selective antegrade cerebral perfusion (SACP) (74±23min). Stent-graft placement into the true lumen was successful in all but one case (99%). Ascending aortic replacement was performed in 91/106 (86%), aortic valve repair/replacement in 49/106 (46%), coronary artery bypass grafting (CABG) in 17/106 (16%) and mitral valve repair in 2/106 (2%). Cardiopulmonary bypass (CPB) and cardiac arrest times were 242±64 and 144±44min, respectively. In-hospital mortality was 12% (13/106; six acute, seven chronic AD) and new strokes observed in 5/106 (5%). The false lumen (FL) was evaluated in 96/106 (91%) patients postoperatively. At first follow-up computed tomography (CT)-examination, thoracic FL thrombosis was 93% (76 complete, 13 partial) and 58% (31 complete, 25 partial) in the thoraco-abdominal aorta. CONCLUSIONS By combining arch replacement with downstream stent grafting, one-stage repair of complex aortic dissection with almost unanimous thoracic FL thrombosis can be achieved at acceptable perioperative risk.

Cardiopulmonary bypass affects cognitive brain function after coronary artery bypass grafting.

BACKGROUND The causes for cognitive impairment after coronary artery bypass grafting (CABG) have long been a topic for debate. METHODS We prospectively followed 308 consecutive, unselected survivors of CABG at our institution. In addition to determination of clinical measurements, cognitive brain function was measured objectively by P300 auditory-evoked potentials before CABG, at 7-day and at 4-month follow-up. Standard psychometric tests (Trail Making Test A, Mini Mental State Examination) were also performed. RESULTS At 7-day follow-up cognitive P300 auditory-evoked potentials were significantly impaired compared with preoperative levels (peak latencies: 376 +/- 40 ms versus 366 +/- 37 ms, p = 0.0001). P300 measurements were almost normalized at 4-month follow-up (peak latencies: 369 +/- 33 ms, p = NS versus preoperative). Standard psychometric tests failed to detect this subclinical cognitive impairment. Multiple regression analysis revealed that use of cardiopulmonary bypass was the only independent predictor of impaired cognitive brain function at 7-day (p < 0.0001) and 4-month follow-up (p = 0.0008). The presence of diabetes mellitus (p = 0.0135) or concomitant repair of significant carotid artery stenosis (p = 0.0049) was predictive of late improvement of cognitive brain function at 4-month follow-up. CONCLUSIONS Objective cognitive P300 auditory-evoked potential measurements demonstrate that the use of cardiopulmonary bypass is the only predictor of short- and long-term cognitive brain dysfunction after CABG. Interestingly, the presence of diabetes mellitus and concomitant repair of a significant carotid artery stenosis were predictive for long-term cognitive benefit.

Aortic arch surgery using bilateral antegrade selective cerebral perfusion in combination with near-infrared spectroscopy

OBJECTIVE Near-infrared spectroscopy (NIRS) complements online monitoring of cerebral oxygenation during aortic arch surgery. Its addition targets at an increase of safety of a complex procedure employing bilateral antegrade cerebral perfusion (BACP) and circulatory arrest under tepid blood temperatures. We report the outcome of NIRS-guided aortic arch surgery using BACP with moderate hypothermic circulatory arrest (MHCA). METHODS Between December 2006 and December 2008, NIRS was used in 13 patients (mean age: 67.5 ± 11.3 years) undergoing aortic arch repair using BACP combined with MHCA. The diagnosis was atherosclerotic thoracic aneurysms in eight and acute aortic dissection in five patients. Seven patients had a hemi-arch replacement, six underwent frozen stent-graft arch replacement and four patients had concomitant procedures such as coronary artery bypass grafting (CABG) or aortic valve surgery. Our regimen of employing an algorithm for adaptation of perfusion modalities included the threshold of the drop in regional cerebral oxygen saturation <55% and/or a drop in the total oxygen index (TOI) of 15-20% assessed by the means of NIRS. RESULTS The mean MHCA was 35 ± 16min and lowest bladder temperature was 26 ± 1.2°C. The mean TOI pre-MHCA was 66 ± 6.5%. Twelve out of 13 patients underwent bilateral perfusion because of unilateral drops below the threshold level of TOI (mean: 44±7.9%). In three patients, an organic psychosyndrome was observed. No patient developed permanent neurological dysfunction. CONCLUSION NIRS-guided BACP during MHCA allows a safe approach to complex aortic arch surgery. The drop of brain oxygenation values in the contralateral hemisphere during unilateral ACP strongly suggests the routine use of BACP, when circulatory arrest under tepid temperatures is used.

Release of neuron-specific enolase and S100 after implantation of cardioverters/defibrillators.

ObjectiveRepeated induction of ventricular fibrillation with ensuing alterations in electroencephalogram and jugular venous oxygen saturation is common practice during insertion of transvenous implantable cardioverters/defibrillators. We investigated whether these functional changes are also associated with cerebral injury. DesignProspective study. SettingUniversity hospital. PatientsWe studied 45 patients undergoing implantable cardioverter/defibrillator insertion. Eleven patients with cardiac pacemaker implantation, which was performed in the same manner yet without the necessity to induce ventricular fibrillation, served as controls. Measurements and Main ResultsSerum neuron-specific enolase and S100 were determined before, immediately postoperatively, and 2 hrs postoperatively. In a randomly composed subgroup, neuron-specific enolase was also determined 6 and 24 hrs after surgery. Implantable cardioverter/defibrillator patients only showed an increase of both markers postoperatively. Median neuron-specific enolase values climbed from a preoperative 9.9 to 12.3 and 14.4 &mgr;g/L at 2 and 24 hrs after surgery, respectively. This increase was associated with the number of shocks and the cumulative time in circulatory arrest. The highest median S100 level (0.075 &mgr;g/L) was reached 2 hrs after the procedure. Neuron-specific enolase and S100 were extremely elevated (13.7 and 0.970 &mgr;g/L, respectively) in one patient after an extended episode of ventricular fibrillation. Plasma hemoglobin levels were in the normal range in implantable cardioverter/defibrillator patients throughout the observation period. ConclusionsApparently, even brief successive periods of global cerebral ischemia cause neuronal damage without obvious severe neurologic deficits. However, they may be related to subtle postoperative neurologic or cognitive dysfunctions that a number of implantable cardioverter/defibrillator patients exhibit after implantation.

Translumbar treatment of type II endoleaks after endovascular repair of abdominal aortic aneurysm

The modality of treatment and the appropriate time point to treat type II endoleaks after endovascular repair of abdominal aortic aneurysms (EVAR) remain controversial issues. The purpose of the present study was to assess the efficacy of translumbar embolization of type II endoleaks after endovascular repair of aortic aneurysm repair. Eighty-four consecutive patients after EVAR were analyzed for the onset of type II endoleaks. Of these, five patients had experienced translumbar embolization after ineffective intraartrial approach to exclude the endoleak. A combination of several liquid embolic agents was used as sealant. Post-procedural contrast-enhanced ultrasound (CEUS) was used to document the outcome of the embolization. Translumbar embolization was successful in four patients. Complete sealing of the nidus was seen on CEUS 24 h after the procedure. In one patient with a duplication of the inferior vena cava, the procedure was aborted because an additional type Ib endoleak was found. The procedure was well tolerated by all patients. The translumbar approach to treat growing aneurysm sacs in patients with persistent type II endoleaks is safe and well tolerated. The immediate post-interventional outcome as documented on CEUS is promising. Long-term follow-ups are yet to be performed.

Is the transpulmonary pressure gradient a predictor for mortality after orthotopic cardiac transplantation

Elevated pulmonary vascular resistance (PVR) is a well‐known risk factor for right ventricular failure after orthotopic cardiac transplantation. The influence of preoperative transpulmonary pressure gradient (TPG) and PVR on post‐transplant 30 days mortality was evaluated. To analyze the response of PVR and TPG to cardiac transplantation, we analyzed 718 adult patients undergoing primary cardiac transplantation. Indications for operation were: 35.2% ischemic cardiomyopathy (ICM), 61.2% idiopathic dilated cardiomyopathy (DCM), and 3.3% other diagnosis (e.g. hypertrophic cardiomyopathy). The mean age (51.9) and the mean ischemic time (169.7 min) were comparable between 30 days survivors and nonsurvivors. Students t‐tests and chi‐square analysis were used to compare data from 30‐day survivors and nonsurvivors. Statistical significance was defined as P < 0.05. Fishers exact test and multiple logistic regression analysis was performed to evaluate the relationship between hemodynamic parameters and outcome after transplantation. Primary end‐point was 30 days mortality and secondary end‐point long‐term survival of patient groups with different TPG and PVR values. In survivors the mean TPG was 10.3 ± 5.1 (mean ± SD) vs. 13 ± 6.6 in patients who died after transplantation (P = 0.0012). The PVR was 2.6 ± 1.4 vs. 3.5 ± 2.2 (P = 0.0012). In multivariate logistic regression, the parameters TPG and PVR exhibit a significant influence between survivors and nonsurvivors after cardiac transplantation within 30 days (TPG: P = 0.0012; PVR: P = 0.0012). The mortality rates in patients with TPG > 11 mmHg and PVR < 2.8 Wood units or TPG < 11 mmHg and PVR > 2.8 Wood units were comparable to those with TPG < 11 mmHg and PVR < 2.8 mmHg. The TPG is an important predictor in nonrejection‐related early mortality after orthotopic cardiac transplantation. The determination of TPG in combination with PVR is a more reliable predictor of early post‐transplant survival than PVR alone.

Repair of stent graft-induced retrograde type A aortic dissection using the E-vita open prosthesis †

OBJECTIVES Stent graft-induced retrograde type A dissection is a life-threatening complication after endovascular treatment of acute aortic type B dissections. METHODS From August 2005 to February 2011, retrograde aortic dissection occurred in 4 of 29 patients (13.8%) undergoing thoracic endovascular aortic repair (TEVAR) for acute complicated aortic type B dissection. Three patients underwent emergent surgical conversion immediately after TEVAR. The operative strategy was a combined surgical and endovascular approach (frozen elephant trunk technique) using a specially designed hybrid prosthesis (Jotec E-vita open). All operations were performed under moderate hypothermia (25-28°C) and selective bilateral antegrade cerebral perfusion. The mean duration of circulatory arrest was 56 ± 7 min. Operative data and the outcome of surgery were analysed retrospectively. Data were analysed retrospectively in the limited number of patients. RESULTS All patients survived the surgical procedure. No stroke, paraplegia, renal failure or other major complications occurred. Postoperative CT scans revealed perigraft thrombus formation and stable aortic dimensions in all patients after 6 months. In one patient, the retrograde dissection remained primarily undetected and untreated. The patient died suddenly, with no clinical signs, within 7 days after stent graft implantation. Autopsy revealed cardiac tamponade due to retrograde type A aortic dissection. CONCLUSIONS Retrograde aortic dissection type A is a serious complication of thoracic endovascular repair of acute aortic type B dissection. Despite the small number of patients investigated in this study, the frozen elephant trunk technique appears to be a feasible bail-out strategy for the treatment of these acute aortic events.

Fate of the False Lumen After Combined Surgical and Endovascular Repair Treating Stanford Type A Aortic Dissections

BACKGROUND The purpose of this study was to evaluate the alterations of the aorta by using a new combined surgical and endovascular technique for the treatment of aortic type A dissections. The diameter of the descending aorta, the implanted stent graft, and the false lumen were evaluated. METHODS Between August 2005 and February 2009, 14 patients (aged 49 +/- 13 years; 11 men, 3 women) with type A dissection in the aorta were operated on the thoracic aorta by the frozen elephant trunk technique. The size dynamics of the false lumen were analyzed by deducting the diameter of the stent graft obtained on computed tomography from the maximum dimension of the aorta. RESULTS The technical success rate was 100%. All patients survived during the follow-up period. The mean follow-up period was 21.4 months. No redisection or aortic rupture occurred during the follow-up period. Postoperative computed tomography scans showed complete thrombus formation of the false lumen in the perigraft space within the entire zone of the stented segment of the hybrid prosthesis during the first 2 weeks after surgery in 12 patients (86%), whereas all patients showed complete obliteration of the false lumen at the 3-month control. The follow-up computed tomography scan obtained after 12 months revealed shrinkage of the false lumen in 9 patients (64%). CONCLUSIONS The combined surgical and endovascular technique described in this report proved effective for the treatment of extended aortic lesions. The perigraft space thrombosed completely and had shrunken after successful placement of the stent graft.