Quantitative blood flow evaluation of vasodilation-stress compared with dobutamine-stress in patients with end-stage liver disease using 82Rb PET/CT.

BACKGROUND: Our aim was to determine if end-stage liver disease (ESLD) is associated with an attenuated response to vasodilator-stress or dobutamine-stress using 82Rb-PET MPI with blood flow quantification. METHODS AND RESULTS: Pre-liver transplant patients who had a normal dipyridamole-stress (n = 27) or dobutamine-stress (n = 26) 82Rb PET/CT MPI study with no identifiable coronary artery calcium were identified retrospectively and compared to a prospectively identified low-risk of liver disease dipyridamole-stress control group (n = 20). The dipyridamole-stress liver disease group had a lower myocardial flow reserve (MFR) (1.89 ± 0.79) than the control group (2.79 ± 0.96, P < .05). The dobutamine-stress group had a higher MFR than both other groups (3.69 ± 1.49, P < .05). A moderate negative correlation between MELD score and MFR was demonstrated for the dipyridamole-stress liver disease group (r = - 0.473, P < .05). This correlation was not observed for the dobutamine-stress liver disease group (r = - 0.253, P = .21). The liver failure group as a whole (n = 53) had a higher resting myocardial blood flow (0.97 ± 0.33 mL/min/g) than the control group (0.82 ± 0.26, P < .05). CONCLUSION: Dipyridamole demonstrates an attenuated vasodilatory response in ESLD patients compared to a non-ESLD control group related to higher resting blood flow and comparatively reduced stress blood flow. Dobutamine does not demonstrate this effect implying it may be the preferred pharmacologic MPI stress agent for ESLD patients.

Cardiac EASE (Ensuring Access and Speedy Evaluation)--design of a single point of entry and a multidisciplinary team to reduce waiting times in the Canadian health care system.

Out-patient cardiac consultation in academic group practices often lacks a coordinated intake process, making it difficult to perform prospective testing or to direct undifferentiated consultations to the cardiologist with the shortest waiting list. We created a programmatic approach, with a single point of entry to improve the efficiency of cardiology consultation, without departing from the Canada Health Act. The purpose of this paper is to describe the design of Cardiac EASE.

Cardiac EASE (Ensuring Access and Speedy Evaluation) - the impact of a single-point-of-entry multidisciplinary outpatient cardiology consultation program on wait times in Canada.

BACKGROUND: Universal access to health care is valued in Canada but increasing wait times for services (eg, cardiology consultation) raise safety questions. Observations suggest that deficiencies in the process of care contribute to wait times. Consequently, an outpatient clinic was designed for Ensuring Access and Speedy Evaluation (Cardiac EASE) in a university group practice, providing cardiac consultative services for northern Alberta. Cardiac EASE has two components: a single-point-ofentry intake service (prospective testing using physician-approved algorithms and previsit triage) and a multidisciplinary clinic (staffed by cardiologists, nurse practitioners and doctoral-trained pharmacists). OBJECTIVES: It was hypothesized that Cardiac EASE would reduce the time to initial consultation and a definitive diagnosis, and also increase the referral capacity. METHODS: The primary and secondary outcomes were time from referral to initial consultation, and time to achieve a definitive diagnosis and management plan, respectively. A conventionally managed historical control group (three-month pre-EASE period in 2003) was compared with the EASE group (2004 to 2006). The conventional referral mechanism continued concurrently with EASE. RESULTS: A comparison between pre-EASE (n=311) and EASE (n=3096) revealed no difference in the mean (+/- SD) age (60+/-16 years), sex (55% and 52% men, respectively) or reason for referral, including chest pain (31% and 40%, respectively) and arrhythmia (27% and 29%, respectively). Cardiac EASE reduced the time to initial cardiac consultation (from 71+/-45 days to 33+/-19 days) and time to a definitive diagnosis (from 120+/-86 days to 51+/-58 days) (P<0.0001). The annual number of new referrals increased from 1512 in 2002 to 2574 in 2006 due to growth in the Cardiac EASE clinic. The number of patients seen through the conventional referral mechanism and their wait times remained constant during the study period. CONCLUSIONS: Cardiac EASE reduced wait times, increased capacity and shortened time to achieve a diagnosis. The EASE model could shorten wait times for consultative services in Canada.

Supratherapeutic response to ezetimibe administered with cyclosporine.

OBJECTIVE: To report the case of a patient who underwent orthotopic heart transplant (OHT) and demonstrated a supratherapeutic response to ezetimibe when administered with cyclosporine. CASE SUMMARY: Ezetimibe 10 mg/day was added to the lipid-lowering regimen (atorvastatin 40 mg/day) of a 64-year-old male patient after OHT to achieve a target low-density lipoprotein cholesterol (LDL-C) level < or = 97 mg/dL, as recommended by national guidelines. After 2 months of ezetimibe, the patient's LDL-C level had decreased by 60% to 51 mg/dL. Subsequently, the dose of ezetimibe was reduced to 5 mg/day and, after another 2 months, a repeat lipid panel revealed LDL-C 57 mg/dL. DISCUSSION: Hyperlipidemia is a common problem among heart transplant recipients. Combination therapy using a statin plus ezetimibe appears to be an attractive option to achieve target lipid levels in this population. However, the manufacturer warns that ezetimibe should be administered cautiously in patients concomitantly receiving cyclosporine. Unpublished data suggest a pharmacokinetic interaction between ezetimibe and cyclosporine that results in a significant 2.3- to 12-fold increase in exposure to total ezetimibe. An objective causality assessment in this case revealed that this supratherapeutic LDL-C reduction was probably related to coadministration of ezetimibe and cyclosporine. A potential mechanism to explain this interaction might be an alteration in glucuronidation induced by cyclosporine. CONCLUSIONS: When ezetimibe is prescribed for patients concomitantly receiving cyclosporine, it should be initiated at a lower than recommended dose (> or = 5 mg/day) and titrated upward. Careful and consistent monitoring of patients on this combination is also advised.