Michael J. Jurmann

Advances in aortic arch surgery.

From 1980 to January 1991, 130 patients (89 men and 41 women, aged 22 to 76 years; mean age, 52 years) underwent 133 interventions on the aortic arch. Aneurysm was diagnosed in 57 patients, whereas 29 had chronic and 44 acute aortic dissection. In 67 instances a partial and in 35 instances a total arch replacement was performed. The distal arch was approached through a left thoracotomy in 14 patients. Local interventions (n = 17) included surgical reconstruction and glue procedures. Additionally, 55 patients required aortic valve replacement, preferably with composite grafts (n = 46), whereas the valve was reconstructed in 14. Procedures were performed using hypothermia (nasopharyngeal temperature, 11 degrees to 25 degrees C) and circulatory arrest (mean time, 27 minutes). Early mortality was 13.9% at the first operation on the aortic arch. Early deaths included 7 of 57 patients with aortic aneurysm (12.3%), 2 of 29 patients with chronic dissection (6.9%), and 9 of 44 patients with acute dissection (20.5%). Neurological (n = 6) and cardiac events (n = 5) were the most common causes of early death. Since 1987, 7 of 88 patients have died for an overall mortality of 8.0%. With growing experience, proper indication, and adequate operative strategy including the use of circulatory arrest in hypothermia, operation on the aortic arch can be performed with an acceptable risk.

Influence of Inflow Cannula Length in Axial-flow Pumps on Neurologic Adverse Event Rate: Results From a Multi-center Analysis

BACKGROUND The application of axial-flow pumps in patients with end-stage heart failure reveals a significantly reduced infectious complication rate as compared with rates observed with pulsatile devices. The remaining adverse event rate relates mainly to thromboembolic complications with neurologic consequences. We investigated the dependence of the neurologic adverse event rate on the length of the inflow cannula. METHODS A total of 216 consecutive patients with an axial-flow pump (INCOR; Berlin Heart GmbH, Berlin, Germany) were included in a retrospective multi-center analysis. In 138 patients, a short inflow cannula (24-mm tip length into the left ventricle), and in 78 patients a long inflow cannula (tip length 34 mm) was applied. RESULTS Patients with a long inflow cannula (LC) demonstrated a better survival rate than those with a short inflow cannula (SC) at the end of the observation period (LC, 63.4%; SC, 52.9%; p = 0.05). The thromboembolic adverse event rate was also significantly lower. Only 3 of the 78 patients (3.8%) with an LC had a thromboembolic adverse event (thromboembolic events per patient-year = 0.11) as compared with 32 (23.2%) of SC patients (thromboembolic events per patient-year = 0.50, p < 0.001). CONCLUSIONS Patients with a long inflow cannula had a better survival rate and a lower incidence of cerebrovascular adverse events than patients with a short inflow cannula.

Bivalirudin provides rapid, effective, and reliable anticoagulation during off-pump coronary revascularization: Results of the "EVOLUTION OFF" trial

In the EVOLUTION OFF trial, we evaluated the safety and efficacy of bivalirudin during off-pump coronary artery bypass grafting as compared with heparin-protamine. In this subanalysis of EVOLUTION OFF data of bivalirudin-treated patients, we assessed the pharmacokinetics (PK) and effectiveness of bivalirudin anticoagulation to achieve target activated clotting time (ACT)+ values. Data from 101 patients were assessed. A bolus of 0.75 mg/kg of bivalirudin was followed by a continuous infusion of 1.75 mg · kg−1 · h−1 during the grafting procedure. An ACT+ value of >300 s was the target. In four patients, PK data for bivalirudin were obtained. Only in exceptional cases were repeat fractional boluses or an increase of the infusion rate required. Assessment of the PK data showed a mean concentration of bivalirudin after the initial bolus of 11.0 ± 0.53 &mgr;g/mL and a mean concentration during infusion of 11.2 ± 2.32 &mgr;g/mL. Pearson’s correlation between bivalirudin concentrations and ACT+ values was 0.92. Bivalirudin PK data consistently exceeded concentrations of 6.5 &mgr;g/mL, which have been evaluated as effective during percutaneous coronary intervention. The correlation between bivalirudin levels and ACT+ values was good, and the target ACT+ values were almost always achieved. These results suggest that bivalirudin, given according to the current protocol, provides reliable and effective anticoagulation during off-pump coronary artery bypass graft surgery.

Tactics and techniques of aortic arch replacement.

Operations on the nondissected and dissected aortic arch still pose challenges in terms of the need for and extent of aortic replacement. Our approaches to these lesions are described against the background of 204 operations (58 aneurysms, 54 chronic dissections, and 92 acute dissections), in terms of cerebral protection, procedural choices, and operative technique. Arch anastomoses sparing the supraaortic vessels had shorter periods of circulatory arrest (17.2 min) when compared to tubular arch replacement, with insertion of some or all of these vessels (33.7 min). Early death rates due to cerebral complications were lowest in acute dissections (3/14 fatalities, with two patients showing preoperative cerebral compromise). Based on our experience, we recommend doing subtotal or total arch repiacement in aneurysms regardless of cause. Radical arch surgery should be avoided in acute dissections whenever feasible. instead, the arch should be explored and a blood‐tight distal anastomosis made, going beyond any entry tears encountered in that aortic portion. (J Card Surg 1994;9:538–547)

Pulmonary reperfusion injury: evidence for oxygen-derived free radical mediated damage and effects of different free radical scavengers.

Blood granulocyte-mediated reactions involving generation of oxygen-derived free radicals have recently been shown to be capable of causing injury to the lungs. These findings suggest a similar mechanism also to be involved in the development of pulmonary ischemia/reperfusion injury. In the present study, therefore, the effects of three oxygen-derived free radical scavengers, superoxide dismutase (SOD; 1 mg/kg), catalase (20,000 IU/kg) and allopurinol (45 mg/kg), were evaluated during reperfusion in a rabbit model after 2 h normothermic ischemia of the lung. During reperfusion, ischemic lungs were found to have an elevated pulmonary vascular resistance, increased total and extravascular lung water content, and decreased arterial oxygen tension (PaO2) compared to control animals. SOD and catalase, but not allopurinol, were able to reduce pulmonary injury by lowering the pulmonary vascular resistance, but could not prevent pulmonary damage as shown by total lung water (TLW) or PaO2. It is concluded that oxygen-derived free radicals such as hydrogen peroxide and the superoxide anion may play an important role in precipitating pulmonary injury after ischemia. The failure of xanthine oxidase inhibition (allopurinol) to exert protective effects may suggest that oxygen-derived free radical generation following pulmonary ischemia occurs predominantly via leukocyte-mediated reactions.

Outpatients on mechanical circulatory support

BACKGROUND As waiting periods for heart transplantation have lengthened, the application of long-term mechanical circulatory support (MCS) has become more common in patients presenting with cardiogenic shock. Anticipating increased long-term MCS, a policy to discharge patients home has been instituted. This study compares the results of outpatient on MCS to a group of patients remaining hospitalized. METHODS We report our 10-year experience with 108 patients on MCS, who were supported for more than 3 months. Group A consisted of 38 patients (25 Novacor, 13 Berlin Heart) who underwent assist implantation from 1996 to 2001. They had a mean support time of 454 days (range 100 to 1074 days) and spent a mean of 326 days (range 20 to 769 days) at home. Group B consisted of 70 patients (24 Novacor, 46 Berlin Heart) who underwent assist implantation between 1991 and 2000. They had a mean support time of 234 days (range 95 to 795 days) and were not discharged. The patients were monitored for complications, hospital readmissions, and causes of death including infections and thromboembolic and bleeding events during the MCS time. RESULTS Group A total mortality was 16% (6/38). Two patients died from cerebral embolism, one from cerebral hemorrhage, two from systemic infection, and one from multiorgan failure. Thirty-two patients (84%) required 95 readmissions to the hospital due to cerebral embolism (n = 9), bleeding (n = 1), wound infections (n = 23), coagulation disorder (n = 13) for heart transplantation (n = 5), and (n = 44). In group B the mortality was 43% (30/70) for noncardiac reasons and thus significant higher (p = 0.004, chi2 test). Causes of death were cerebral embolism (n = 5), cerebral hemorrhage (n = 7), systemic infection (n = 14, significantly higher, p = 0.04, chi2 test), and multiorgan failure (n = 4). CONCLUSIONS Our experience demonstrates that MCS can be used in outpatients without increased mortality and with an acceptable rate of readmissions (2.8/patient). It ensures the survival of the patient, enables recovery from multiorgan failure, and offers an acceptable quality of life.

Malperfusion of the Thoracoabdominal Vasculature in Aortic Dissection

Ischemic damage to vital organs supplied by the thoracoabdominal aorta greatly increases the overall risk of aortic dissection. Of 320 patients operated upon for aortic dissection since 1985, 33 (10.3%) underwent operations directed at the relief of malperfusion (15/158 acute type A; 9/18 acute type B; 4/78 chronic type A; 5/66 chronic type B). Organs affected were the kidneys in 32; the bowel in 20; and the spinal cord in 1, while critical lower extremity ischemia was present in 11 patients. In total, 64 vascular areas were affected. Fenestration of the dissecting membrane with or without infrarenal grafting was the procedure performed most frequently in 25, followed by replacement of the descending or thoracoabdominal aorta in 6, and bypass grafting or dlrect revascularization of individual side branches in 6. Six other operations targeted at the affected organs were done. Twenty‐four patients underwent one‐stage operation for malperfusion; in 11, early reoperation after primary aortic repair was necessary, while 2 patients were operated electively. Ten of 33 patients died in hospital, 7 of malperfusion‐induced complications. Of three late deaths, one was related to sequelae of malperfusion. We conclude that Immediate diagnosis and prompt relief of malperfusion offer the best prospects for patient survival. Membrane fenestration appears to be the method of choice for treating malperfusion in most patients, and must be directed to the level of aortic and/or side branch obstruction. (J Card Surg 1994;9:748–757)

Emergency lung transplantation after extracorporeal membrane oxygenation

In some patients with acute respiratory failure, the native lungs do not recover during extracorporeal membrane oxygenation (ECMO), or complications occur that preclude the meaningful continuation of ECMO therapy. In such cases, emergency lung transplantation (LTx) represents the only therapeutic alternative. Between May 1988 and April 1993, the authors have performed LTx after ECMO support in five of 111 lung or heart-lung transplantations (4.5%). Two patients presented with early graft failure after unilateral LTx. In these patients, ECMO was used as a bridging device to unilateral re-LTx for 1, resp. 11 days. One patient died 6 months post-operatively from chronic rejection; the other underwent a third LTx and is doing well after 42 months. In three further patients already treated with ECMO for 5 to 12 days for ARDS (n = 2) or acute respiratory failure after liver and kidney transplantation, the native lungs did not recover (n = 2) or pulmonary hemorrhage developed. The last patient (unilateral LTx) and one of the former (bilateral LTx for ARDS) are long-term survivors (12, 30 months). The remaining patient (unilateral LTx for ARDS) had severe multiorgan failure at the time of his operation and died intraoperatively. The authors conclude that ECMO no longer represents a contraindication to subsequent LTx. Their results also support the continued investigation of this combined therapeutic approach.

Differences in Pulsatile and Non-pulsatile Mechanical Circulatory Support in Long-Term Use

BACKGROUND Non-pulsatile left ventricular assist device (LVADs) systems have attained more interest for long-term use. We present the results of mechanical circulatory support (MCS) with pulsatile and non-pulsatile LVAD in use in patients for more than 1 year. METHODS Between February 1999 and February 2006, 48 patients (mean age, 51; range, 20-72 years) received an LVAD: 24 each had pulsatile (Group A) and non-pulsatile MCS (Group B). RESULTS Mean support time was 862 days (range, 366-1876 days) in Group A, and 631 days (range 368-1129 days) in Group B. In Group A, 20 patients (80%) were at home for more than 1 year, in Group B, 21 patients (88%). Five VAD-related complications occurred (4 pump exchanges, 1 controller exchange). Echocardiography showed better LV unloading, and the LV end-diastolic diameter was significantly lower in Group A (60 mm) than in Group B (69 mm). Neither the number of driveline/cannula infections nor the number of bleeding and embolic complications differed significantly between groups. Thirty-two patients received heart transplants, 11 died, and 5 still have the VAD. CONCLUSIONS Although echocardiographic data show that pulsatile LVADs seem to better unload the LV, this could not be confirmed by data from right ventricle catheterization. Owing to sufficient LV unloading, longer device durability, less need of anticoagulation therapy, and greater quality of life, non-pulsatile devices are preferred for long-term use. Nevertheless, both systems can be used with good quality of life and an acceptable rate of complications for extended periods of time.

Aprotinin in fibrin tissue adhesives induces specific antibody response and increases antibody response of high-dose intravenous application☆☆☆★

BACKGROUND In cardiac operations, aprotinin therapy is used either locally as a component of commercially available fibrin tissue adhesives, intravenously, or combined. Our aim was to examine the formation of aprotinin-specific antibodies with regard to the application mode. METHODS Sera of 150 patients who had undergone cardiac operations and were receiving aprotinin therapy for the first time were sampled before the operation and at medians of 3.5 and 13.3 months after the operation. Aprotinin-specific IgG including all subgroups and aprotinin-specific IgE were analyzed. Aprotinin was given locally (as contained in fibrin sealant; n = 45; median dose, 6000 KIU), intravenously (n = 46; 2.000 x 10(6) KIU), and combined (n = 59; 2.012 x 10(6) KIU). RESULTS At 3.5 months, the prevalence of aprotinin-specific IgG antibodies was 33% (15/45 patients) after local, 28% (13/46 patients) after intravenous, and 69% (41/59 patients) after combined exposure (P =.0001). At 13.3 months, the prevalence of aprotinin-specific IgG antibodies was 10% (4/41 patients) after local, 31% (13/42 patients) after intravenous, and 49% (28/57 patients) after combined exposure. Total aprotinin dose was similar in patients who were antibody positive and negative. Before the operation, no aprotinin-specific antibodies were detected. Aprotinin-specific IgE were not found after the operation. CONCLUSION Local aprotinin contact induces a specific immune response and reinforces that of intravenous exposure. The antibody spectrum is identical to the immune response induced by intravenous exposure. Any exposure should be documented. For use in cardiac operations as a hemostyptic, the necessity itself and alternatives for aprotinin as a stabilizing agent merit consideration.