Piero Maria Mikus

Extracorporeal Membrane Oxygenation for Primary Allograft Failure

OBJECTIVE Herein we have reported our experience concerning the usefulness of extracorporeal membrane oxygenation (ECMO) in heart transplant patients. PATIENTS AND METHODS Between July 2002 and March 2007, 11 heart transplant patients, namely, 8 men and 3 women of overall mean age of 49.4 +/- 13.9 years (range, 19-62 years) with primary graft failure underwent ECMO implantation. Two patients had pulmonary hypertension; 3 had been transplanted with hearts from marginal donors. At the time of implantation, all were in severe cardiogenic shock despite maximal inotropic support. In 6 patients, the ECMO was implanted centrally in the operating room when there was failure of weaning of cardiopulmonary bypass. Among the 5 remaining patients, ECMO was implanted peripherally in the intensive care unit, during the first 60 hours, including 3 cases of hemodynamic instability and 1 of irreversible cardiac graft arrest. The last patient was implanted on day 30 after transplantation because of acute rejection. RESULTS Mean pump outflow was 2.7 +/- 0.4 L/min/m(2). One patient died on circulatory support due to a cerebral hemorrhage. Ten patients were weaned from ECMO after a mean duration of 9.1 +/- 6.9 days (range, 1-18 days). All of them were successfully discharged. No retransplantation occurred. CONCLUSION Rapid operating room or bedside placement of ECMO allowed stabilization of hemodynamics with potential myocardial recovery in patients with cardiac graft failure.

Activity–rest stimulation of latissimus dorsi for cardiomyoplasty: 1-year results in sheep

BACKGROUND In dynamic cardiomyoplasty electro-stimulation achieves full transformation of the latissimus dorsi (LD); therefore, its slowness limits the systolic support. Daily activity-rest could maintain partial transformation of the LD. METHODS Sheep LD were burst-stimulated either 10 or 24 hours/day. Before and 2, 4, 6, and 12 months after stimulation, LD power output, fatigue resistance, and tetanic fusion frequency were assessed. Latissimus dorsi were biopsied at 6 months, and sheep sacrificed at 12 months. RESULTS After 1 year of 10 hours/day stimulation LD was substantially conserved and contained large amounts of fast type myosin. From 2 months to 1 year of stimulation the power per muscle of the daily rested LD was greater than that of the left ventricle, being three to four times higher than in the 24-hour/day stimulation. CONCLUSIONS If extended to humans, these results could be the rationale for the need of a cardiomyostimulator, whose discontinuous activity could offer to patients the long-standing advantage of a faster and powerful muscle contraction.

Pulmonary endarterectomy: an alternative to circulatory arrest and deep hypothermia: mid-term results.

BACKGROUND The current surgical technique for pulmonary endarterectomy (PEA) involves the use of deep hypothermia and circulatory arrest at 18 degrees C (DHCA). Our experience started in 2004 when we decided to use an original alternative strategy which consists of avoiding deep hypothermia and subsequent circulatory arrest by using moderate hypothermia at 26 degrees C, and maintaining a bloodless field. This can be achieved by means of negative pressure in the left heart chambers and appropriate pump flow modulation in order to maintain the mixed venous oxygen saturation (SVO(2)) higher than 65%. MATERIALS AND METHODS From June 2004 to June 2007, 40 consecutive patients were operated on in our department with this strategy. The aim of this article is to report the early results for all patients and the complete six-month follow-up for 30 subjects who have reached this end-point at the time of writing. The mean temperature during extracorporeal circulation was 25.9 degrees C; core temperature was lowered to 21 degrees C in only one patient and an 8 min DHCA was performed in order to complete the PEA. RESULTS Two patients died (6.6%): one on the third postoperative day due to myocardial infarct, requiring an ECMO implantation. The other patient died from septic shock. The six-month follow-up, performed in all other patients, included clinical and hemodynamic evaluation. Pulmonary vascular resistance (PVR) decreased from 793.5+/-284 dyn/cm/s(-5) to 286+/-143 (p=0.000). A comparable reduction of mean pulmonary arterial pressure and an increase of cardiac output were also observed. CONCLUSIONS The results confirm that adequate removal of pulmonary artery obstructive lesions can also be achieved with an operative procedure that avoids or reduces the use of DHCA while allowing a bloodless field during PEA interventions. This technique may limit the well known adverse effects of DHCA due to organ hypoperfusion, improving the postoperative recovery of the patients.

Stress Echocardiography as a Gatekeeper to Donation in Aged Marginal Donor Hearts: Anatomic and Pathologic Correlations of Abnormal Stress Echocardiography Results

BACKGROUND Owing to the shortage of donor hearts, the criteria for acceptance have been considerably expanded. Pharmacologic stress echocardiography is highly accurate in identifying prognostically significant coronary artery disease, but brain death and catecholamine storm in potential heart donors may substantially alter the cardiovascular response to stress. This study assessed correlates of an abnormal resting/stress echocardiography results in potential donors. METHODS From April 2005 to December 2007, 18 marginal candidate donors (9 men) aged 58 +/- 5 years were initially enrolled. After legal declaration of brain death, all marginal donors underwent bedside echocardiography, with baseline and (when resting echocardiography was normal) dipyridamole (0.84 mg/kg in 6 min) or dobutamine (up to 40 microg/kg/min) stress echo. Non-eligible hearts (with abnormal rest or stress echo findings) were excluded and underwent cardioautoptic verification. RESULTS Resting echocardiography showed wall motion abnormalities in 5 patients (excluded from donation). Stress echocardiography was performed in the remaining 13 (dipyridamole in 11; dobutamine in 2). Results were normal in 7, of which 6 were uneventfully transplanted in marginal recipients. Results were abnormal in 6, and autoptic verification performed showed coronary artery disease in 5, and initial cardiomyopathy in 1. CONCLUSIONS Bedside pharmacologic stress echocardiography can safely be performed in candidate heart donors, is able to unmask occult coronary artery disease or cardiomyopathy, and shows potential to extend donor criteria in heart transplantation. Further experience with using marginal donors is needed before exact guidelines can be established.

Cardiac transplantation from a carbon monoxide intoxicated donor.

Heart transplantation is a demonstrated successful and life-saving treatment for an increasing number of patients. The growth of heart transplantation surgery is limited by the relative lack of suitable donors, and the increasing demand has lead to the expansion of acceptance criteria. Patients succumbing to carbon monoxide (CO) poisoning are usually considered not suitable organ donors and they are routinely rejected in many centers. Although organs from CO poisoning donors have been occasionally used, cardiac transplantation in this scenario remains very uncommon. We report the successful heart transplantation from a CO intoxicated donor, who was previously refused by two other transplantation teams. Standard donor evaluation criteria, transplantation techniques and management were used. Limited cases are described in literature. The present case may increase awareness among emergency department physicians, as well as transplantations teams, that patients dying of CO exposure may be acceptable cardiac donors.

Liver and partial atrium transplantation for chronic Budd-Chiari syndrome.

A 22-year-old man was admitted to our hospital for progressive liver failure with ascites, jaundice, and bleeding from esophagogastric varices due to chronic Budd-Chiari syndrome and antiphospholipid syndrome. Nine years before, a transjugular intrahepatic portosystemic shunt (TIPS) had been placed between the right hepatic vein and the portal vein at another hospital. The patient subsequently developed acute obstruction of the hepatic veins followed by the progressive upward extension of the thrombus, requiring positioning of a second TIPS in the vena cava. Because of complete occlusion of both shunts, the patient developed the symptoms of chronic Budd-Chiari syndrome despite collateral circulation. At our hospital, a computed tomography scan confirmed the presence of a thrombus in the vena cava from the renal veins to the right atrium (Fig. 1). The patient was scheduled for liver and partial right atrium transplantation with cardiopulmonary bypass. The abdominal incision started when the ascending aorta, the superior vena cava, and the right femoral vein had been cannulated and normothermic cardiopulmonary bypass had been instituted. This strategy helped us to decompress the portal vein and the collateral circulation and permitted an easier approach to the right atrium. The recipient hepatectomy was performed with the resection of the vena cava from the renal veins to the right atrium and with the opening of the diaphragm through the central fibrous body (Fig. 2). Occlusion of the caval lumen up to the right atrium was confirmed (Fig. 3A,B). The graft was retrieved from a 66-year-old woman considered to be not suitable for heart donation; this allowed us to harvest the liver with the right atrium en bloc (Fig. 4A). In the recipient, the donor atrium was brought into the chest through the diaphragm for the atriumatrium anastomosis (white circle in Fig. 4B). The anastomosis of the inferior vena cava, portal vein, hepatic artery, and bile duct was performed in a standard fashion. During the procedure, hemodynamic parameters remained stable, the cold ischemia time was 7 hours, and 12 units of packed red blood cells were required. The postoperative course was uneventful, and the patient was discharged after 4 weeks. We believe that the key point for the success of this procedure was the planning of liver and partial atrium transplantation with cardiopulmonary bypass. The use of the donor atrium ensured enough tissue to remove the recipient vena cava together with the portion of the atrium affected by the thrombus and easy accomplishment of the atrium-atrium anastomosis. The cardiopulmonary bypass and the partial atrium transplantation due to the atrium being affected by the thrombus, reported in other cases, permitted optimal management of the intraoperative hemodynamic conditions, counterbalancing the need for heparin infusion during extracorporeal circulation.

Kidney transplantation combined with other organs in Bologna: an update.

BACKGROUND We retrospectively reviewed our experience in combined liver-kidney (L-KT) and heart-kidney (H-KT) transplantations. PATIENTS AND METHODS Between January 1997 and April 2007, we performed 25 L-KT and 5 H-KT. Patient mean age was 51+/-8 years in L-KT and 43+/-11 years in H-KT. The main cause of liver failure was chronic viral hepatitis (14 cases). Etiology of heart failure was dilated cardiomyopathy and hypertrophic cardiomyopathy (4 and 1 patients, respectively). The main causes of renal failure in L-KT were chronic glomerulonephritis (n=8) and polycystic disease (n=7). Etiology of renal failure in H-KT was interstitial nephropathy (n=2), vascular nephropathy (n=2), and chronic glomerulonephritis (n=1). RESULTS Mean follow-up was 32+/-26 months in L-KT and 24+/-17 months in H-KT. Immunosuppression was cyclosporine-based (n=4) or tacrolimus-based (n=21) in L-KT and cyclosporine-based in H-KT. Acute rejection rate was 8% for both liver and kidney in L-KT; 80% (mild) for heart and 40% for kidney in H-KT. In the L-KT group, there was no primary graft nonfunction (PGNF). Two patients experienced liver delayed graft function (DGF); 1 patient required postoperative dialysis. One-year graft and patient survivals were both 84% and overall graft and patient survival was 76%. In the H-KT group, 3 patients needed postoperative dialysis and 1 required a cardiac assistance device for 48 hours; overall graft and patient survival was 100% with good cardiac and renal functions. CONCLUSION Our experience confirmed that H-KT and L-KT are safe procedures, offering good long-term results.

Extracorporeal right to left atrial bypass to treat right ventricular failure.

Graft right ventricular failure after heart transplantation, secondary to preoperative functional pulmonary hypertension, was successfully managed in a 49-year-old patient using an extracorporeal right to left atrial bypass. We comment on the case and discuss the type of mechanical assistance used.

Circulatory assist with centrifugal pump as a bridge to recovery: mathematical analysis.

Mechanical circulatory support is an essential issue in the management of patients with end-stage cardiac failure. The aim of this study is to evaluate the efficacy of temporary support with a centrifugal blood pump as bridge to heart function recovery or bridge to transplantation. Heart recovery is achieved by improving ventricular mechanical working conditions with proper modifications of preload and afterload. This article assesses the advantages of a novel “cardiac chambers” cannulation setting versus the traditional one, in the case of biventricular or isolated right ventricular failure. The study was conducted using a numerical computer model based on the work by Guyton, Sagawa, Westerhof, and Noordergraaf. Simulation of the planned trials was achieved by changing the model parameters, the pump angular velocity, and the inflow and outflow settings. (Int J Artif Organs 2007; 30: 604–10)