Provision of anaesthesia for porcine cardiac transplantation at the veterinary school in Trinidad and Tobago

A successful heterotopic cardiac transplantation was performed between sibling female Yorkshire Juvenile swine. Adequate pre-medication with azaperone and a smooth induction were ensured for both pigs, which were anaesthetized simultaneously with sodium thiopentone followed by endotracheal intubation and intermittent positive pressure ventilation. Inhalation anaesthetic agents were used for maintenance, neuromuscular blockade was achieved with cisatracurium and both fentanyl and tramadol were used to provide analgesia. Invasive monitoring was used in both the donor and recipient. Central venous pressure (CVP) was maintained at > 10 cm H2O and mean arterial pressure (MAP) > 60 mmHg. Heparin was injected during the surgical dissection of the heart in the donor to prevent coronary thrombosis and prior to aortic side clamping for end-to-side anastomosis of the donor heart in the recipient abdomen. After transplantation, the cardiovascular parameters of the recipient showed a MAP of 85-105 mmHg and a CVP of 8-10 cm H2O while echocardiography of the transplanted heart confirmed an ejection fraction (EF) of 80. A functional anaesthetic team was assembled and trained to provide anaesthesia for porcine cardiac transplantation. The transplanted heart suffered pump failure after 69 days and was excised for performance of tissue analysis

The initial Trinidad experience with Cine MRI in clinical cardiology

We describe the initial Trinidad experience with Magnetic Resonance Imaging (MRI) and Cine MRI as a diagnostic tool in clinical cardiology. Six patients from the following categories were referred for Cine MRI evaluation: congenital heart disease, valvular heart disease, aortic diseases, cardiomyopathy and intracardiac mass. All patients underwent echocardiography. MRI and Cine MRI were performed on all patients using a Siemens Magnetom 1.0 Tesla MR system at MRI Trinidad and Tobago Ltd. Selected patients underwent Angiography and/or computed tomography (CT) scanning. Clinical data and images of the six patients evaluated are described. MRI and Cine MRI provided excellent anatomical and functional details of the heart and aorta in five patients with dissection of the aorta, aneurysm of the ascending aorta, suspected left ventricular apical thrombus, infiltrative cardiomyopathy and arrhythmogenic right ventricular dysplasia. Technical difficulty was experienced with one patient who had a congenital defect (common atrium). In this study, Cine MRI provided excellent images in all but one patient. This new noninvasive technique enhanced diagnostic capabilities and facilitated management in patients with certain cardiovascular diseases.

Stenting of partial and total coronary occlusions in Trinidad and Tobago

In order to evaluate the efficacy and safety of coronary stenting, we reviewed the first 32 consecutive patients (34 vessels) who underwent elective coronary stenting during the period August 1999 to August 2000 inclusive at the Digital Lab installed at the Eric Williams Medical Sciences Complex, Trinidad and Tobago. Aspirin, heparin and ticlopidine were used routinely. Abciximab was used in selected cases (38). The mean age of patients was 55 +/- 10 years. Eighty-one per cent were male, 52 were hypertensive and 21 were diabetic. Sixty-five per cent had severe angina. Prior Coronary Artery Bypass Grafting (CABG) was performed in 3 and previous Percutaneous Transluminal Coronary Angioplasty (PTCA) in 3. Multivessel disease was present in 43. The mean left ventricular ejection fraction was 53 +/- 12. The culprit lesion was located in either the native left anterior descending (LAD) coronary artery (53), right coronary artery (RCA) (31), circumflex artery 13 and saphenous vein graft (3). The mean baseline diameter stenosis was 91 +/- 9 and this was reduced to 13 +/- 33 after stenting. Procedural success was 100 for 26 partially occluded vs 50 for 8 totally occluded vessels. For the total occlusions, procedural success was inversely related to the duration of the occlusion. There were no cases of death, acute vessel closure, Q-wave myocardial infarction, repeat PTCA or emergent Coronary Artery Bypass Graft (CABG) during and following the procedure. Distal embolization occurred in one patient. The mean duration of hospital stay was one day (for 30 outpatient cases). One patient had recurrence of symptoms with a negative stress test. No patient underwent repeat angiography during the first year of follow-up. Coronary stents were successfully implanted at a tertiary care facility in the Caribbean with low in-hospital morbidity and mortality. Stents markedly reduced the diameter stenosis of the coronary lesion during PTCA. The incidence of clinical restenosis was low. Coronary revascularisation can be successfully achieved by coronary stenting in the Caribbean.

Coronary artery bypass graft outcome: the Trinidad and Tobago experience

The study is retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in-hospital and intermediate-term follow-up results. The mean age of patients was 59 +/- 10 years and 78 were male. Sixty-four per cent were of East Indian descent, whereas 16 were of African descent. Forty-eight per cent of the patients were hypertensive, 46 were diabetic, 33 had hyperlipidaemia, 20 had a recent history of cigarette smoking and 16 were obese. Sixty-five per cent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5 of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 +/- 15. Wall motion abnormalities were seen in 67 of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91, 78, 54 and 5, respectively. Many patients (67) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 +/- 0.8 days. In-hospital mortality was 3.9 (8/205). The most frequent post-operative complication was haemorrhage (2.6). Acute renal failure occurred in 2.1; pulmonary collapse, 1.6; stroke, 1 and cardiac arrest, 1. Both sternal wound infections and systemic sepsis occurred in 0.5. Intermediate-term follow-up data were obtained for 92 (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow-up period, 7 patients (3.4) died. Angina severity was reduced from a mean CCS score of 2.61 +/- 0.95 before CABG to 1.22 +/- 0.55 at the time of follow-up (p < 0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.

The feasibility of a porcine model of acute coronary occlusion and reperfusion using off-pump coronary artery bypass grafting

We developed an open-chest porcine model of acute coronary occlusion and surgical reperfusion, and attempted to prevent intra-operative ischaemic ventricular fibrillation (VF) by a Retrograde Intracoronary Glyceryl trinitrate (RIG) infusion into the occluded vessel. Five Yorkshire pigs (weight 50 +/- 1.1 kg), randomized into 3 groups, underwent median sternotomy under general anaesthesia. One pig (Group 1, control) underwent sternotomy and pericardiotomy only. Four pigs underwent acute left anterior descending (LAD) coronary occlusion. Two pigs were not reperfused (Group 2). Two pigs underwent surgical reperfusion (Group 3) via left internal mammary artery (LIMA) grafting to the LAD using the Off-Pump Coronary Artery Bypass (OPCAB) technique. Ischaemic injury was assessed using 7-lead electrocardiography (ECG) and transthoracic/epimyocardial echocardiography (ECHO). Group 1: transient intraoperative hypotension and VF occurred. Successful resuscitation and 10-week survival (until sacrifice) with normal left ventricular (LV) function was achieved. Group 2: there were ECG and ECHO evidence of acute LV ischaemic dysfunction in both pigs. The surviving pig had persistent anterior hypokinesis at 8 1/2 months. The other died intra-operatively following progressive ischaemic LV dysfunction despite resuscitative attempts. Group 3: the surviving pig had normal LV function at 8 months. Initial anterior LV akinesis normalized within 7 days. The other developed post-occlusion haemodynamic instability and died intra-operatively despite reperfusion. In this porcine model, acute LAD artery occlusion modified by the novel RIG infusion technique, followed by surgical reperfusion (OPCAB) is feasible. This model would facilitate further development of OPCAB surgical expertise and understanding of the pathophysiology of ischaemia-reperfusion injury.

Two-year mortality and its determinants following acute myocardial infarction in Trinidad and Tobago

The purpose of this study was to determine the occurrence of coronary artery disease risk factors in patients presenting with acute myocardial infarction(AMI) to a tertiary care institution in Trinidad and to determine the factors associated with increased mortality following AMI. All patients admitted to the Eric Williams Medical Sciences Complex (EWMSC) between January 1 and December 31, 1996, with a diagnosis of AMI were identified using the hospital admissions and discharge diagnosis databases. Demographic, clinical and laboratory variables were extracted from the hospital case records of patients with confirmed AMI. Sixty-one AMI patients (38 men) were admitted during the study period. Mean age of admittance was 60 ñ 11 years with an ethnic case mix of thirty-nine (62 percent) of East Indian descent, eight (13 percent) of African descent, twelve (20 percent) mixed ethnicity and three of Caucasian descent. Thirty patients (49 percent) were hypertensive. Thirty-two patients (53 percent) were diabetic and eighteen patients (30 percent) gave a history of cigarette smoking. The mean left venticular ejection fraction was 53 ñ 14 percent. The mean serum cholesterol from 29 patients was 228.2 ñ 49.0 mg/dl. Increasing age, female gender, an ejection fraction less than 40 percent, non treatment with streptokinase and in-hospital ventricular fibrillation were associated with poor survival. Multiple regression analyses identified three independent predictors of mortality. These were gender (p = 0.04), in-hospital ventricular fibrillation (p = 0.001) and an ejection fraction less than 40 percent (p = 0.02). Diabetes mellitus, hypertension, hyperlipidaemia and cigarette smoking were prevalent amongst patients presenting with AMI. Ventricular function was a major determinant of two-year mortality following AMI. Aggressive risk factor modification is recommended to prevent both first and recurrent coronary events.