Stable patients with suspected myocardial ischemia: comparison of machine-learning computed tomography-based fractional flow reserve and stress perfusion cardiovascular magnetic resonance imaging to detect myocardial ischemia.

BACKGROUND: Machine-Learning Computed Tomography-Based Fractional Flow Reserve (CT-FFRML) is a novel tool for the assessment of hemodynamic relevance of coronary artery stenoses. We examined the diagnostic performance of CT-FFRML compared to stress perfusion cardiovascular magnetic resonance (CMR) and tested if there is an additional value of CT-FFRML over coronary computed tomography angiography (cCTA). METHODS: Our retrospective analysis included 269 vessels in 141 patients (mean age 67 ± 9 years, 78% males) who underwent clinically indicated cCTA and subsequent stress perfusion CMR within a period of 2 months. CT-FFRML values were calculated from standard cCTA. RESULTS: CT-FFRML revealed no hemodynamic significance in 79% of the patients having ≥ 50% stenosis in cCTA. Chi2 values for the statistical relationship between CT-FFRML and stress perfusion CMR was significant (p < 0.0001). CT-FFRML and cCTA (≥ 70% stenosis) provided a per patient sensitivity of 88% (95%CI 64-99%) and 59% (95%CI 33-82%); specificity of 90% (95%CI 84-95%) and 85% (95%CI 78-91%); positive predictive value of 56% (95%CI 42-69%) and 36% (95%CI 24-50%); negative predictive value of 98% (95%CI 94-100%) and 94% (95%CI 90-96%); accuracy of 90% (95%CI 84-94%) and 82% (95%CI 75-88%) when compared to stress perfusion CMR. The accuracy of cCTA (≥ 50% stenosis) was 19% (95%CI 13-27%). The AUCs were 0.89 for CT-FFRML and 0.74 for cCTA (≥ 70% stenosis) and therefore significantly different (p < 0.05). CONCLUSION: CT-FFRML compared to stress perfusion CMR as the reference standard shows high diagnostic power in the identification of patients with hemodynamically significant coronary artery stenosis. This could support the role of cCTA as gatekeeper for further downstream testing and may reduce the number of patients undergoing unnecessary invasive workup.

High-flow priapism: a combined interventional approach with angiography and colour Doppler.

Traumatic high-flow priapism caused by a pathologic influx from lacerated arteries to the cavernous bodies is usually treated by transcatheter arterial embolisation. The purpose of this study was to evaluate a combined interventional approach with intraoperative perineal colour Doppler ultrasound (US) while performing the embolisation procedure. Our aim was to reduce radiation exposure and application of iodinised contrast media. To achieve an optimal position of the angiography catheter directly before or in the fistula, instead of several x-ray examinations with contrast media, a perineal colour Doppler US examination was performed while saline or US contrast media were injected through the catheter. The flow pattern allows the assessment of the occlusion of the fistula and the intact flow in the arteries that were not damaged. In four patients (unilateral fistula: 1, bilateral fistulas: 3) with traumatic high-flow priapism, this technique was performed combined with a conventional angiographic control of the embolisation. Seven embolisation sessions were performed. Only in one case, a dislocation of a microcoil required a second session. In all cases, the priapism disappeared immediately after the final session, leading to a restored erectile function. This combined approach may reduce the exposure to radiation and contrast media, especially in children, who often suffer from multiple fistulas and need more than one session. The procedure also prevents an occlusion of intact arteries that affects the penile perfusion and increases the risk of erectile dysfunction.