Recipient

The majority of patients referred to Toronto General Hospital heart failure team have ischemic (60%) or idiopathic (25%) cardiomyopathy with the minority having valvular or congenital problems.

Currently accepted indications and contraindications for heart transplantation are presented in Table 21.1.

Potential candidates for heart transplantation undergo a thorough evaluation (Table 21.2) and are assessed by a multidisciplinary committee to allow for the equitable distribution of scarce donor resources. The average time to transplant at TTH is 165 days. Across Canada there is a priority staging system for status based on clinical condition (5 status categories).

Table 2Ï.Ï. Indications and contraindications

Indications

1. end stage heart disease refractory to other surgical or medical management

2. NYHA III-IV symptoms with maximal medical therapy and prognosis for 1 year survival < 75%

3. no other major organ or system disease

4. emotionally stable with social support

5. medically compliant and motivated

Contraindications incurable malignancy major system illness irreversible major organ disease active systemic infection emotional instability ? age obesity irreversible pulmonary hypertension

Table 2Ï.2. TTH precardiac transplant assessment protocol

Consultation

Investigation

cardiology

right and left heart catherizations

cardiovascular surgery

two-dimensional echocardiogram

respiratory

electrocardiogram

transplant immunology

pulmonary function tests

psychiatry

arterial blood gases

psychology

chest x-ray

dental surgery

abdominal ultrasound

social work

antibody screen HBV, HCV, HIV

chaplaincy

HLA typing, anti-HLA antibodies

transplant co-ordinator

digoxin levels

antibody titres CMV, herpes simplex,

Epstein Barr, toxoplasmosis

Laboratory

ABO blood type and screen

CBC, ESR, smear, reticulate

PT, PTT, bleeding time

lytes, BUN, creatinine, uric acid

glucose (fasting, 2hr PC)

cholesterol, triglycerides

liver function tests

protein electrophoresis

thyroid function tests

stools (parasites, c/s, blood)

urinalysis, 24hr Cr clearance and protein

Patients are optimized medically with digoxin, diuretics and vasodilators (ACEI, hydralazine and p-blockers). Outpatient dobutamine is not used as the results have been less than promising. Decompensated patients are admitted to hospital and managed with IV inotropes or vasodilators. At TTH mechanical support is limited to endotracheal intubation and the IABP as ventricular assist devices are not used as a bridge to transplantation. More recently, in carefully selected patients, salvage surgery for ischemia, valves and left ventricular volume reduction has been performed.

The recipient is admitted to hospital when an appropriate donor is identified. Most patients have elevated pulmonary artery pressures, which may be easy to control if treatment is commenced a few hours prior to transplantation. Although a patient may be on the list, recent uncontrolled pulmonary hypertension will preclude a transplant. While no absolute rules exist, general guidelines for maximally acceptable pulmonary artery pressure (PAP) include: a) absolute systolic PAP > 45 mm Hg, b) PAP which are 1/2 systemic (provided systemic > 80 mm Hg), c) calculated pulmonary vascular resistance < 6 woods, d) transpulmonary gradient = mean PAP - mean PCWP < 10-15 mm Hg.

Because the number one cause of pulmonary hypertension in these patients is an increase in total body water, most patients will receive an intravenous diuretic. It is imperative that this practice of minimal fluid is maintained in the operating room prior to surgery. Any hypotensive episodes should be treated with inotropes and not fluids.

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