Results of Serial Myocardial Perfusion Imaging in End-Stage Renal Disease.

For patients awaiting renal transplantation, there is guideline consensus on the need for ischemia testing but no agreement on the frequency of repeat testing. Moreover, there are no data in this population evaluating changes in ischemia assessed with serial myocardial perfusion imaging. Consecutive patients (n = 649) with end-stage renal disease (ESRD) were referred for cardiovascular risk stratification before renal transplantation between 2007 and 2013. Of these, 151 patients (54 ± 9 years) underwent 2 stress-rest technetium-99m single-photon emission computed tomographic (SPECT) studies with CT attenuation correction in accordance with regional guidelines, which recommend repeat imaging in high-risk subjects who have not undergone renal transplantation within 3 years. An abnormal perfusion result was defined as a summed stress score ≥4. The median interval between imaging was 39 months. At baseline, 28% of patients (42/151) had abnormal SPECT perfusion, half with a fixed defect. Nine subjects (6%) underwent revascularization between SPECT studies after the baseline imaging demonstrated an ischemic perfusion defect size affecting ≥10% of the myocardium. On repeat imaging, 60% (25/42) had abnormal perfusion. In the 72% (109 of 151) with normal baseline SPECT perfusion, 19% (21/109) demonstrated new ischemia at follow-up and 3% (3/109) had an ischemic perfusion defect size ≥10%. The development of new-onset ischemia was associated with systolic hypertension (p = 0.015), serum phosphate (p = 0.043), and Agatston score (p = 0.002), but not diabetes (p = 0.12). In conclusion, there is a high frequency of new-onset ischemia in patients with ESRD awaiting renal transplantation. Further study is needed to define the optimal timing for repeat stress testing.

Prognostic Utility of Calcium Scoring as an Adjunct to Stress Myocardial Perfusion Scintigraphy in End-Stage Renal Disease.

Coronary artery calcium score (CACS) is a strong predictor of adverse cardiovascular events in the general population. Recent data confirm the prognostic utility of single-photon emission computed tomographic (SPECT) imaging in end-stage renal disease, but whether performing CACS as part of hybrid imaging improves risk prediction in this population is unclear. Consecutive patients (n = 284) were identified after referral to a university hospital for cardiovascular risk stratification in assessment for renal transplantation. Participants underwent technetium-99m SPECT imaging after exercise or standard adenosine stress in those unable to achieve 85% maximal heart rate; multislice CACS was also performed (Siemens Symbia T16, Siemens, Erlangen, Germany). Subjects with known coronary artery disease (n = 88) and those who underwent early revascularization (n = 2) were excluded. The primary outcome was a composite of death or first myocardial infarction. An abnormal SPECT perfusion result was seen in 22% (43 of 194) of subjects, whereas 45% (87 of 194) had at least moderate CACS (>100 U). The frequency of abnormal perfusion (summed stress score ≥4) increased with increasing CACS severity (p = 0.049). There were a total of 15 events (8 deaths, and 7 myocardial infarctions) after a median duration of 18 months (maximum follow-up 3.4 years). Univariate analysis showed diabetes mellitus (Hazard ratio [HR] 3.30, 95% CI 1.14 to 9.54; p = 0.028), abnormal perfusion on SPECT (HR 5.32, 95% CI 1.84 to 15.35; p = 0.002), and moderate-to-severe CACS (HR 3.55, 95% CI 1.11 to 11.35; p = 0.032) were all associated with the primary outcome. In a multivariate model, abnormal perfusion on SPECT (HR 4.18, 95% CI 1.43 to 12.27; p = 0.009), but not moderate-to-severe CACS (HR 2.50, 95% CI 0.76 to 8.20; p = 0.130), independently predicted all-cause death or myocardial infarction. The prognostic value of CACS was not incremental to clinical and SPECT perfusion data (global chi-square change = 2.52, p = 0.112). In conclusion, a perfusion defect on SPECT is an independent predictor of adverse outcome in potential renal transplant candidates regardless of the CACS. The use of CACS as an adjunct to SPECT perfusion data does not provide incremental prognostic utility for the prediction of mortality and nonfatal myocardial infarction in end-stage renal disease.

Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy.

BACKGROUND: Left ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics. METHODS: Patients with NICM (n = 116; age: 62.8 ± 13.2 years; 67% male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (-) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation. RESULTS: Despite a similar LVEF (24.3 vs. 27.5%, p = 0.20), patients with MWF (32 [24%]) had lower global circumferential strain (Ɛcc: -6.6% vs. -9.4 %, P = 0.004), but similar longitudinal (Ɛll: -7.6 % vs. -9.4 %, p = 0.053) and radial (Ɛrr: 14.6% vs. 17.8% p = 0.18) strain. Compared with - MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (-0.38 ± 0.1 vs. -0.56 ± 0.3 s(-1), p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs. 28 %, P <0.001). In addition, +MWF was associated with reduced LV diastolic strain rates (DSRcc: 0.34 vs. 0.46 s(-1); DSRll: 0.38 vs. 0.50s(-1); DSRrr: -0.55 vs. -0.75 s(-1); all p <0.05). CONCLUSIONS: MWF is associated with reduced LV global circumferential strain, strain rate and torsion. In addition, MWF is associated with rigid LV body rotation and reduced diastolic strain rates. These systolic and diastolic disturbances may be related to the increased risk of pump failure observed in patients with NICM and MWF.