Small vessel disease after heart transplantation: impact of immunologic and nonimmunologic risk factors*

Beneficial effect of female gender on long-term survival after heart transplantation

BACKGROUND

We aimed to test whether stenotic microvasculopathy affects the more beneficial course in female cardiac transplant recipients.

METHODS

We studied 873 patients (35/151 premenopausal women aged < or =40 years) who underwent primary heart transplantation. In 7750 biopsies harvested within the first posttransplant year endothelial disease and stenotic microvasculopathy were evaluated by light microscopy (Hematoxylin and Eosin). Kaplan-Meier and Cox regression analyses were performed for major cardiac events (MACE; lethal myocardial infarction, sudden cardiac death, graft failure, and cardiac retransplantation).

RESULTS

Stenotic microvasculopathy was found equally in men (38%) and women (39%). Allografts from premenopausal female-to-male transplants more frequently developed endothelial disease (78% vs. 65%; P=0.021) and stenotic microvasculopathy (46% vs. 28%, P=0.024). Beyond the first 5 posttransplant years women presented MACE less often than men, independently of donor gender and stenotic microvasculopathy (P=0.0001). Multivariate regression analysis found women to be at lower risk for MACE (Relative Risk [RR] 0.38; 95% Confidence Interval [CI] 0.17-0.81), whereas stenotic microvasculopathy (RR 2.15; 95% CI 1.42-3.26) and treated diabetes (RR 1.65; 95% CI 1.08-2.52) indicated a higher risk for MACE.

CONCLUSIONS

Stenotic microvasculopathy has prognostic impact on survival of male and female cardiac recipients; however, it does not affect the more beneficial course of women in the long-term follow-up.

Quilty in biopsy is associated with poor prognosis after heart transplantation

We tested if Quilty (endocardial infiltration of lymphocytes) in routinely processed endomyocardial biopsy is associated with poor outcome after heart transplantation (HTx). Biopsies (n=9829) harvested within the first post-transplant year from 938 patients (778 men, mean age 49 years) were evaluated for Quilty and acute cellular rejection (according to the International Society for Heart and Lung Transplantation, ISHLT, classification). Transplant vasculopathy was evaluated by coronary angiography, and severe stenosis was found in 19% of patients. Survival was tested by Kaplan-Meier and Cox regression analyses for all-cause mortality and major cardiac events (lethal acute cellular rejection, graft loss or myocardial infarction). We found 1840 (19%) Quilty-positive biopsies in 487 Quilty-positive patients (52%). Quilty was more prevalent in women (p=0.038) and younger men (p=0.001), and was correlated with ISHLT grade 1R (OR 1.45, 95% CI 1.36-1.55; p<0.001) and ISHLT grade 2R (OR 2.48, 95% CI 2.21-3.41; p<0.001). Quilty in any biopsy was associated with a higher all-cause mortality (log rank p=0.045) due to a higher risk for major cardiac event (p=0.0001). Multivariate regression analysis showed Quilty (RR 1.69, 95%CI 1.05-2.73) and transplant vasculopathy (RR 2.78, 95%CI 1.68-4.61) as risk factors for major cardiac events and treated hyperlipidemia as lowering the risk for major cardiac events (RR 0.47, 95%CI 0.28-0.77). Quilty is associated with graft loss and poor outcome post HTx. Index biopsy during the first post-transplant year is a useful tool to identify patients at risk and is recommended during routine post-transplant management.

Coronary flow reserve measurement detects transplant coronary artery disease in pediatric heart transplant patients

BACKGROUND

Cardiac allograft vasculopathy (CAV) in patients who have undergone heart transplantation leads to graft dysfunction and is still the major concern for long-term survival. Evaluation of coronary flow velocity reserve (CFR) has been established for diagnosis of CAV. Systemic application of adenosine vs intracoronary testing for CFR has been validated in adults; however, its accuracy in pediatric patients has not yet been proven.

METHODS

CFR was prospectively measured in 33 clinically asymptomatic pediatric heart transplant recipients. CFR measurements were made in the left anterior descending (LAD) artery using a 0.014-inch Doppler FloWire (Cardiometrics). CFR was defined as the ratio of hyperemic (after adenosine injection) to basal (before adenosine) average peak velocity (APV). Adenosine (Adrekar) was administered by intracoronary (15 or 30 mug bolus) and systemic (0.1 mg/kg) injection in each patient. Epicardial CAV was evaluated in coronary angiograms (Stanford criteria) and microvasculopathy was diagnosed in endomyocardial biopsies (evidence of luminal stenosis) blinded to clinical data.

RESULTS

Thirty-three patients were included in this study. Their median age (range) was 11.9 (1.4 to 17) years and median post-transplant time 4.3 (1 to 11.7) years. Seventeen of the 33 patients had epicardial CAV (mainly peripheral obliterations or B1 and B2 lesions) and microvascular CAV. Epicardial CAV only was found in 4 patients and microvasculopathy only was present in only 1 patient. CFR was significantly reduced in patients with epicardial CAV and microvasculopathy when compared with patients without any signs of CAV: 206 +/- 53 vs 276 +/- 39 (p < 0.001) for the systemic application and 213 +/- 50 vs 271 +/- 45 (p = 0.004) for the intracoronary application.

CONCLUSIONS

CFR and coronary vasoreactivity to adenosine are decreased in pediatric patients with CAV and correlate with histopathologic and angiographic evidence of microvascular disease. Measurement of CFR with intracoronary and systemic application of adenosine is comparable, while systemic application is necessary for non-invasive measurement of CFR in pediatric patients.

Prognostic impact of microvasculopathy on survival after heart transplantation: evidence from 9713 endomyocardial biopsies

BACKGROUND

Epicardial vasculopathy has been shown to be associated with poor outcome after heart transplantation. We demonstrate that histologically proven stenotic microvasculopathy is a novel prognostic factor for long-term survival.

METHODS AND RESULTS

In 9713 biopsies harvested within the first posttransplantation year from 873 patients (83% male; mean age, 49.1+/-0.6 years), light microscopic evaluations (x200) were performed for microvasculopathy, defined as stenotic endothelial and/or medial disease. Prevalence of severe epicardial vasculopathy was defined by presence of > or = 75% luminal stenosis in coronary angiography (available in 611 of 873 patients), which was present in 118 of 611 patients (19%). For Kaplan-Meier analysis, we defined fatal cardiac events as lethal acute myocardial infarction, sudden cardiac death, and graft failure. Stenotic microvasculopathy was present in 379 of 873 patients (43%) and was due to medial (345/379; 91%) rather than endothelial disease (2/379; 1%) or a combination of both (31/379; 8%; P<0.001). Endothelial disease (median [95% CI], 12.07 [10.69 to 13.44] versus 12.73 years [10.16 to 15.30]; P=0.3329) and nonstenotic medial disease (12.44 [11.14 to 13.74] versus 12.43 years [10.51 to 14.35]; P=0.4047) did not decrease overall survival or time to fatal cardiac event. Stenotic microvasculopathy was associated with poor overall survival (10.90 [9.16 to 12.60] versus 13.40 years [11.79 to 15.07]; P=0.0374) and decreased freedom from fatal cardiac events (1, 5, 10 years, 95.6+/-1.4%, 86.9+/-2.3%, 75.5+/-3.1% versus 99.1+/-0.5%, 96.8+/-1.0%, 89.8+/-1.9%; P<0.0001). This finding was independent of epicardial transplant vasculopathy (P=0.0031).

CONCLUSIONS

Stenotic microvasculopathy is frequent in routinely processed biopsies and a new prognostic factor for long-term survival after heart transplantation.