Background: Available data suggests that the use of intravascular ultrasound (IVUS) for guidance of percutaneous coronary interventions (PCI) leads to implantation of larger stent sizes and improves prognosis of patients undergoing complex procedures. We aimed to examine, how the utilization of IVUS affects patient survival in a longitudinal registry of patients undergoing conventional coronary angiography.

Methods: The present analysis is based on a registry of patients undergoing conventional coronary angiography at our department between 2004 and 2019. Patients with missing follow-up information were excluded. Incidence of death of any cause during follow-up was recorded. Cox regression analysis was used to determine the association of IVUS-utilization with incident morality. 

Results: Overall, data from 31.305 coronary angiography exams (mean patient age 64.9±12.5 years, 70.1% male) were included in our analysis, of which 5.043 procedures (16.1%) were guided by IVUS. Patients undergoing IVUS as part of the angiography were slightly younger (64.4±11.3 vs. 65.0±12.7 years, p=0.0003), more frequently male (76.2 vs. 68.9%, p<0.0001), had lower LDL-cholesterol levels (103.2±38.1 vs. 107.8±39.5 mg/dl, p<0.0001), and had more frequently hypertension (84.1 vs 80.1%, p<0.0001) as compared to patients not receiving IVUS diagnostic. During a mean follow-up of 3.4±3.6 years, 5.299 deaths (16.9%) occurred. Mortality was significantly lower following IVUS-guided coronary procedures (13.1%) as compared to procedures without IVUS (16.7%, p<0.0001, figure 1). In Cox regression analysis, utilization of IVUS was associated with a 36% reduction of morality (Hazard ratio [95% confidence interval]: 0.64 [0.59 -0.70], p<0.0001, figure 1). Effect sizes remained stable upon adjustment for traditional risk factors (0.63 [0.58-0.68], p<0.0001). Interestingly, also for purely diagnostic coronary angiography examinations, utilization of IVUS was assoisted with improved prognosis, independent of age, gender, and traditional risk factors (0.62 (0.55-0.69), p<0.0001). Those patients more frequently received medical therapy with asprin (84.4% vs. 62.0%, for IVUS vs. no IVUS, p<0.0001), statins (73.3% vs. 51.7%, p<0.0001), and non-statin lipid lowering drugs (5.6% vs. 3.9%, p=0.04) comparing with patients recived coronary interventions. Likewise, patients with IVUS examinations were more 1.5-fold more likely to be diagnosed with coronary artery disease (61.5% vs. 39.6%, p<0.0001).

Conclusion: In a large registry cohort of patients undergoing conventional coronary angiography, utilization of IVUS was associated with a 36% reduction of all-cause death during longitudinal follow-up. The beneficial role of IVUS utilizations on long-term survival is present for coronary interventions and diagnostic coronary angiograms. For patients undergoing diagnostic coronary angiograms, utilization of IVUS was associated with a higher frequency of aprin and statin therapy as well as primary discharge diagnosis of CAD. Our results support the use of intravascular imaging for decision making in interventional cardiology. 

Figure 1: Kaplan Meier analysis for the survival of patients undergoing conventional coronary angiography with (red) and without (blue) utilization of IVUS, demonstrating an improved prognosis in patients receiving intravascular imaging (p<0.0001).