RESUMO
BACKGROUND: Angiographic assessment of left main coronary artery (LMCA) stenosis severity can be unreliable. In cases of ambiguity, intravascular ultrasound (IVUS) can be utilised with a minimal lumen area (MLA) of ≥6 âmm2 an accepted threshold for safe deferral of revascularization. We sought to assess whether quantitative computer tomography coronary angiography (CTCA) measures could assist clinicians making LMCA revascularization decisions when compared with IVUS as gold standard. METHODS: Consecutive patients undergoing IVUS assessment of angiographically intermediate LMCA stenosis were included. All patients had undergone 320-slice CTCA <90 days prior to IVUS imaging. Offline quantitative assessment of IVUS- and CT-derived measures were undertaken with the cohort divided into those with significant (s-LMCA) versus non-significant (ns-LMCA) disease using the accepted IVUS threshold. RESULTS: Fifty-eight patients were included, with no difference in mean age (61.5 â± â12.2 vs. 59.7 â± â11.9 years, p â= â0.57), diabetic status (24.2% vs 16.0%, p â= â0.44) or other baseline demographics between groups. Patients with ns-LMCA had larger CT luminal area (8.64 â± â3.91 vs. 5.41 â± â1.54 âmm2, p â< â0.001), larger minimal lumen diameter (MLD) (3.25 â± â0.74 vs. 2.56 â± â0.38 âmm, p â< â0.001) and lower area stenosis (45.74 â± â18.10 vs. 60.93 â± â14.68%, p â= â0.001). There was a significant positive correlation between CTCA and IVUS MLA (r â= â0.68, p â< â0.001) and MLD (r â= â0.67, p â< â0.001). ROC analysis demonstrated CTCA MLA cut-off <8.29 âmm2 provides the greatest negative predictive value and sensitivity in predicting the presence of significant LMCA disease. CONCLUSION: CTCA derived MLA and MLD have a strong correlation with IVUS. A CTCA derived MLA cut-off <8.29 âmm2 showed greatest clinical utility for predicting the need for further assessment, based on IVUS gold standard.
RESUMO
Transcatheter aortic valve implantation (TAVI) with commissural alignment aims to limit the risk of coronary occlusion and maintain good coronary access. However, due to coronary origin eccentricity within the coronary cusp, coronary-commissural overlap (CCO) may still occur. TAVI using coronary alignment, rather than commissural alignment, may further improve coronary access. To compare rates of CCO after TAVI using commissural versus coronary alignment methodology. Cardiac CT scans from 102 patients with severe (tricuspid) aortic stenosis referred for TAVI were analysed. Native cusp asymmetry and coronary eccentricity were defined and used to simulate TAVI using commissural versus coronary alignment. Rates of optimal coronary alignment (< 10° from cusp centre) and severe misalignment (< 15° from coronary-commissural overlap) were compared. Additionally, the impact of valve misalignment during implantation was assessed. The native right coronary artery (RCA) origin was 15.8° (9.5 to 24°) closer to the right coronary cusp/non-coronary cusp (RCC-NCC) commissure than the centre of the right coronary cusp. The native left coronary artery (LCA) origin was 4.5° (0 to 11.5°) closer to the left coronary cusp/non-coronary cusp (LCC-NCC) commissure than the centre of the left coronary cusp (p < 0.01). Compared to commissural alignment, coronary alignment doubled the proportion of optimally-aligned RCAs (62/102 [60.8%] vs. 31/102 [30.4%]; p < 0.001), without a significant change in optimal LCA alignment (62/102 [60.8% vs. 74/102 [72.6%]; p = 0.07). There were no cases of severe misalignment with either strategy. Simulating 15° of valve misalignment resulted in severe RCA compromise risk in 7/102 (6.9%) of commissural alignment cases, compared to none using coronary alignment. Fluoroscopic projection was similar with both approaches. Coronary alignment resulted in a 2-fold increase of optimal TAVI positioning relative to the RCA ostium when compared to commissural alignment without impacting the LCA. Use of coronary alignment rather than commissural alignment may improve coronary access after TAVI and is less sensitive to valve rotational error, particularly for the right coronary artery.