Long-Term Clinical Implications of High-Risk Cardiac Computed Tomography Findings in Patients With Acute Ischemic Stroke.

BACKGROUND: Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking. METHODS AND RESULTS: We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44]). CONCLUSIONS: Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Diagnostic Yield of ECG-Gated Cardiac CT in theAcute Phase of Ischemic Stroke vsTransthoracic Echocardiography.

BACKGROUND AND OBJECTIVES: Guidelines recommend echocardiography to screen for structural sources of cardioembolism in patients with ischemic stroke. Cardiac CT is a promising alternative as a first-line screening method. We aimed to determine whether cardiac CT, acquired during the initial stroke imaging protocol, has a higher yield for detecting high-risk cardioaortic sources of embolism than transthoracic echocardiography (TTE). METHODS: We performed a prospective, single-center, observational cohort study and included consecutive adult patients with acute ischemic stroke who underwent ECG-gated cardiac CT during the initial stroke imaging protocol. Patients also underwent the routine stroke workup, including TTE. The main outcome was the proportion of patients with a predefined high-risk cardioaortic source of embolism on cardiac CT vs TTE in patients undergoing both investigations. RESULTS: Between May 2018 and November 2020, 774 patients with a suspected ischemic stroke underwent hyperacute cardiac CT. We excluded 228 patients with a diagnosis other than ischemic stroke and 94 because they did not provide informed consent. Therefore, 452 patients (59.3% male, median age 72) were included. The median additional scan time of cardiac CT was 6 (interquartile range 5-7) minutes with poor scan quality in only 3%. In total, 350 of the 452 patients (77.4%) underwent TTE, 99 of whom were performed in an outpatient setting. Reasons for not undergoing TTE were death (33, 7.3%) and TTE being too burdensome to perform in the outpatient setting (69, 15.3%). A high-risk cardioaortic source of embolism was detected in 40 of the 350 patients (11.4%) on CT, compared with 17 of the 350 (4.9%) on TTE (odds ratio 5.60, 95% CI 2.28-16.33). Cardiac thrombus was the most frequent finding (7.1% vs 0.6%). The diagnostic yield of cardiac CT in the full study population was 55 of the 452 (12.2%). Among the 175 patients with cryptogenic stroke after the routine workup, cardiac CT identified a cause of the stroke in 11 (6.3%). DISCUSSION: Cardiac CT acquired in the acute phase of ischemic stroke is technically feasible and has a superior diagnostic yield compared with TTE for the detection of high-risk sources of embolism. Cardiac CT may be considered as an alternative to TTE to screen for cardioembolism.

Patient-tailored Contrast Delivery Protocols for Computed Tomography Coronary Angiography: Lower Contrast Dose and Better Image Quality.

PURPOSE: The first objective of this study was to evaluate the efficacy of a patient-tailored contrast delivery protocol for coronary computed tomography angiography (CTCA), in terms of diagnostic coronary attenuation and total iodine load (TIL), by adjusting the iodine delivery rate (IDR) via dilution for body weight and tube voltage (kV), as compared with a protocol with a fixed bolus of contrast in a clinical setting. The secondary objective was to assess the association between the test-bolus data and luminal attenuation in CTCA. MATERIALS AND METHODS: Patients who underwent CTCA with fixed IDR contrast delivery (cohort 1) or with IDR adjusted for body weight and kV settings (70 to 120 kV) (cohort 2) were included, and compared for intravascular luminal attenuation and TIL. The association between intravascular luminal attenuation and test-bolus scan data was investigated with linear regression. RESULTS: In cohort 1 (176 patients), the mean luminal attenuation differed markedly between kV categories, whereas in cohort 2 (154 patients), there were no marked differences. The mean TIL reduced significantly (20.1±1.2 g in cohort 1, 17.7±3.0 g in cohort 2, P<0.001). The peak height of the test-bolus scan was independently associated with luminal attenuation in the ascending aorta, with a 0.58 HU increase per HU peak-height increase (SE=0.18, P<0.001). CONCLUSION: Clinical implementation of a patient-tailored contrast delivery protocol for CTCA, adjusted for body weight and kV, improves luminal attenuation and significantly reduces the TIL. The peak height of the test-bolus scan is associated with luminal attenuation in the ascending aorta in the CTCA scan.