Intravascular Ultrasound Correlates with Coronary Flow Reserve and Predicts the Survival in Angiographically Normal Cardiac Transplant Recipients

Abstract

Objectives: We aimed to determine whether epicardial and intramyocardial arteries were involved concordantly in early cardiac allograft vasculopathy. Methods: Thirty consecutive recipients who had received cardiac transplantation more than 1 year before and had a normal coronary angiogram were enrolled for intravascular ultrasound (IVUS), fractional flow reserve, coronary flow reserve and dipyridamole thallium-201 single photon emission computed tomography. Graft failure including cardiac death and retransplantation served as the primary outcome. Results: Plaque volume index and maximum area stenosis calculated from IVUS measurements correlated with coronary flow reserve deterioration in a subgroup of patients with normal fractional flow reserve (n = 13; r = –0.80, p = 0.001 and r = –0.91, p <0.0001, respectively). After follow-up for 18.4 ± 7.6 months, maximum area stenosis was found to be an independent predictor of graft failure (hazard ratio 1.43, 95% confidence interval 1.08–1.89, p = 0.012). Conclusion: In patients with physiologically normal epicardial coronary arteries, impairment of microvascular integrity correlates with the plaque burden measured by IVUS, suggesting the concordant involvement of both epicardial and resistant vessels in early cardiac allograft vasculopathy. Evident epicardial coronary narrowing on IVUS may predict graft failure in spite of normal coronary angiograms.

PET Assessment of Myocardial Perfusion Reserve Inversely Correlates with Intravascular Ultrasound Findings in Angiographically Normal Cardiac Transplant Recipients

“…Conflicting results in IVUS-and Doppler-derived coronary flow reserve studies (7,8,(28)(29)(30)(31)(32)(33)(34)(50)(51)(52) suggest that the correlation between endothelial dysfunction and coronary changes is complex. Studies in the past have shown that dynamic PET provides information complementary to coronary anatomy.…”

“…Relevant baseline characteristics of the patients are reported in Table 1. All patients received standard immunosuppressive therapy as previously described (7,8,(13)(14)(15). Based on concurrent endomyocardial biopsy findings, none had acute rejection of grade II or higher (according to the system of the International Society for Heart and Lung Transplantation) during the IVUS study (41).…”

Assessment of Microcirculatory Remodeling With Intracoronary Flow Velocity and Pressure Measurements

“…Although coronary microcirculation in heart transplantation patients has been functionally studied by most authors using CFVR, our results suggest that this is not the method of choice for the assessment of microvasculopathy in cardiac allografts, providing an explanation of controversial findings with CFVR in these patients. 33,34 So far, 2 studies have evaluated cardiac allograft microcirculation using techniques other than CFVR: Klauss al 11 using CRI (same methodology as in our work) and Fearon et al 35 using a thermodilution-derived resistance index. However, a comparison with the histological substrate was not performed in either of these studies.…”

Diagnosis and management of coronary allograft vasculopathy in children and adolescents

“…Unfortunately, stents do not offer better long-term results with a late re-stenosis rate around 70%. Drug eluting stents appear to have slightly better results with less restenosis [57,166] . However, only the minority of CAV lesions are amenable for percutaneous revascularization as outlined above and stent angioplasty might only be an option in selected patients.…”

“…In transplanted patients, the exact value of FFR to determine epicardial disease is difficult to establish and results have been inconsistent between series [56,57] . In a publication by Hirohata et al [20] , FFR improved as the microvascular disease deteriorated and therefore, due to the particular interaction between microvascular and epicardial disease that occurs in CAV, FFR might not be the best reflection of epicardial affectation in this situation.…”