Augustine, J.

Hypertension develops soon after organ transplantation using cyclosporine- or FK506-based immunosuppression. Sustained rises in blood pressure require intervention to reduce the risk of intracranial bleeding and other cardiovascular complications. Antihypertensive treatment is complicated by reduced renal function and potential interference with absorption and/or metabolism of cyclosporine or FK506. To manage early and long-term hypertension related to immunosuppression with cyclosporine or FK506 and prednisone following orthotopic liver transplantation, a comprehensive nurse-managed hypertension clinic was developed. Blood pressure, heart rate, and antihypertensive and immunosuppressive regimens were evaluated according to a standard protocol at 1, 4, 12, 24, and 36 months after orthotopic liver transplantation. Data indicate that posttransplantation hypertension develops within the first months after orthotopic liver transplantation and persists indefinitely. If comprehensively managed by the hypertension nurse-clinician, the percentage of controlled hypertension patients can increase over time.

Cyclosporine induces hypertension and wide-spread vasoconstriction after transplantation in addition to reducing kidney function. We studied hemodynamic, renal, and hormonal effects of monotherapy with nifedipine XL (n = 37) in liver transplant recipients within a year after transplant (median, 4.4 months). Systemic hemodynamics were determined with thoracic electrical bioimpedance. Blood pressure before therapy was 172 +/- 4/108 +/- 2 mm Hg. Sixty-four percent of recipients achieved blood pressures less than 140/90 mm Hg mediated by a fall in systemic vascular resistance index (2427 +/- 245 dyne.s.cm-5.m-2 in responders versus 2905 +/- 281 in nonresponders, P < .01). Despite the fall in systemic vascular resistance, glomerular filtration rates were not changed during nifedipine therapy, as measured by both creatinine and iothalamate clearances. Urinary prostacyclin (6-ketoprostaglandin F1 alpha) was suppressed below normal from 2468 +/- 323 ng/d before transplant to 1103 +/- 99 ng/d (P < .01) after transplant and did not change during nifedipine therapy. Urinary thromboxane B2 and plasma renin activity also fell after transplant and remained low during nifedipine. These data demonstrate that nifedipine can reverse systemic vasoconstriction associated with hypertension after transplantation. Systemic effects were not transmitted to the kidney sufficiently to improve glomerular filtration rate or reverse hormonal changes within the kidney. Hence, vascular and functional regulation of the kidney was dissociated from the systemic circulation during nifedipine administration after transplantation.

Although resistant hypertension affects a minority of all hypertensives, this group continues to experience disproportionately high cardiovascular event rates despite newer antihypertensive agents. Hypertension represents an imbalance of hemodynamic forces within the circulation, usually characterized by elevated systemic vascular resistance. We studied the utility of serial hemodynamic parameters in the selection and titration of antihypertensive medication in resistant hypertensive patients using highly reproducible noninvasive measurements by thoracic bioimpedance. Resistant hypertension patients (n=104) were randomized to drug selection based either on serial hemodynamic (HD) measurements and a predefined algorithm or on drug selection directed by a hypertension specialist (SC) in a 3-month intensive treatment program. Blood pressure was lowered by intensified drug therapy in both treatment groups (169±3/87±2 to 139±2/72±1 mm Hg HD versus 173±3/91±2 to 147±2/79±1 mm Hg SC, P <0.01 for systolic and diastolic BP), using similar numbers and intensity of antihypertensive medications. Blood pressures were reduced further for those treated according to hemodynamic measurements, resulting in improved control rates (56% HD versus 33% SC controlled to ≤140/90 mm Hg, P <0.05) and incremental reduction in systemic vascular resistance measurements. Although the number of patients taking diuretics did not differ between groups, final diuretic dosage was higher in the hemodynamic cohort. Our results demonstrate superior blood pressure control using a treatment algorithm and serial hemodynamic measurements compared with clinical judgment alone in a randomized prospective study. Our measurements of thoracic fluid volume support occult volume expansion as a mediator of antihypertensive drug resistance and use of impedance measurements to guide advancing diuretic dose and adjustment of multidrug antihypertensive treatment.