A 54-year-old patient is considered for liver transplantation because of hepatitis C virus-related cirrhosis, Child-Turcotte-Pugh class C. He has pulmonary hypertension (PHT) without evidence of primary lung disease or heart failure. Therapy with inhaled iloprost decreased the mean pulmonary artery pressure (MPAP) from 60 to 42 mmHg. Right ventricular function is good. Would you proceed with transplantation in this patient?
Marius Braun, MD
Pulmonary hypertension in the setting of portal hypertension was described early on by Edwards and colleagues. Although the differentiation between the different categories of PHT is somewhat variable, it is helpful to use the categorization described in the Table.
| Category | MPAP (mmHg) | Systolic PAP (mmHg) |
|---|---|---|
| Mild | 25-34 | 35-44 |
| Moderate | 35-44 | 45-59 |
| Severe | 45-75 | 60-100 |
| Very severe | > 75 | > 100 |
Defined strictly by an MPAP > 25 mm Hg, the incidence of PHT has been reported as high as 20%.
However, the impact of mild-to-moderate PHT was minimal. The poor outcomes associated with the presence of severe PHT in liver transplantation have been described by several groups.
Patients in the latter category suffer from acute right-sided heart failure, often at the time of reperfusion when the myocardium is stunned from release of substances from the newly perfused liver, and occasionally even on days after transplantation, when fluid shifts increase right heart strain.
In the early days of liver transplantation, many patients were only first diagnosed at the time of liver transplantation, when the right heart-pressure catheter was inserted. With increased recognition of the incidence of PHT, pretransplant evaluation usually includes assessment of pulmonary pressures (indirectly by examining right-ventricle and pulmonary artery-valve movement). Echocardiography is a useful screening tool during the evaluation
; however, the need for quantifying the degree of PHT, evaluation of cardiac output, and pulmonary artery-wedge pressure can only be done with right heart catheterization.
Elevations in PHT can be seen in patients with fluid overload and renal failure and do not intrinsically connote PHT. However, echocardiography provides an important assessment of right ventricular function and wall motion as well as the presence of tricuspid valve function, which may be compromised with severe PHT and is a poor prognostic sign.
With the recognition of increased mortality associated with moderate and severe PHT, programs avoided transplanting such patients. In a recent report of a multicenter study, the combination of elevated MPAP and peripheral vascular resistance was associated with denial of liver transplantation.
The use of combined heart-lung-liver transplantation has been described as a successful way to address severe PHT in a patient with liver failure.
However, this application is obviously limited in scope. The utilization of inhaled nitric oxide, prostacyclins, and now phosphodiesterase type-5 inhibitors has changed the outlook of PHT. The group at the University of Maryland first described the successful transplantation of severe PHT following improvement of PAP with the prolonged use of prostacyclin.
However, this treatment is not without significant side effects (ie, diarrhea and flushing) and a high nonresponse rate (60%).
In this patient with an MPAP of 42 mmHg and good right ventricular function, it would seem prudent to check cardiac output. If it is "normal" (ie, hyperdynamic is normal for a patient with cirrhosis), then you could proceed to liver transplantation with judicious selection of the donor organ to minimize postperfusion myocardial dysfunction, careful fluid management, and continued use of prostacyclin intraoperatively and postoperatively.