When cardiologists thread a replacement heart valve through a patient’s femoral artery, they often focus on how narrow or calcified the vessel is. But a new study suggests they should also pay attention to how winding the route is. Researchers at the TUM University Hospital German Heart Center in Munich report that a simple geometric measurement of arterial curvature, known as the tortuosity index, is linked to an increased risk of death within six months of transcatheter aortic valve implantation, one of the most common structural heart procedures performed worldwide.
The study, published in Clinical Research in Cardiology, analyzed 2,002 patients who underwent transfemoral TAVI between April 2011 and January 2023. All patients had high-quality computed tomography angiography scans of their peripheral vessels, allowing the investigators to reconstruct the three-dimensional path of the iliac and femoral arteries with dedicated software. The median age of the cohort was 81 years, 45.2 percent were women, and the median EuroScore II, a measure of surgical risk, was 4.22, reflecting the typically frail population that receives these valves.
The tortuosity index itself is elegantly simple. Using centerline reconstruction of the CT scan, the team measured the true length of the vessel path from the aorto-iliac bifurcation down to the epigastric artery, then divided that by the straight-line distance between the same two points. A perfectly straight vessel would score 1.0. Borrowing from guidelines developed for endovascular aortic aneurysm repair, the researchers classified vessels into four grades and dichotomized patients into a low tortuosity group with an index at or below 1.5 and a high tortuosity group above 1.5.
The results were striking. At six months of follow-up, 7.9 percent of patients in the high tortuosity group had died, compared with 5.2 percent of those in the low tortuosity group, a difference that reached statistical significance. After adjusting for peripheral artery disease, creatinine clearance, and prior myocardial infarction using Cox proportional hazard modeling, a tortuosity index above 1.5 remained independently associated with mortality, carrying a hazard ratio of 1.679. When the index was treated as a continuous variable, each unit increase was associated with an even larger hazard ratio of 3.593.
Perhaps the most intriguing aspect of the finding is that the high tortuosity group was not simply sicker in the conventional sense. Although these patients were older, they actually had a lower prevalence of established mortality-related comorbidities, including diabetes, arterial hypertension, coronary artery disease, and malignancy. This suggests that the excess mortality cannot be explained by a heavier burden of traditional risk factors, and that the winding shape of the arteries may itself carry prognostic information.
The authors propose that vascular tortuosity may act as a marker of frailty and biological aging. Arteries elongate and kink as elastic fibers degrade over decades, and previous work has linked tortuosity in non-atherosclerotic vascular disease to age, aneurysms, and hypertension. In this framing, a highly tortuous iliac artery is less a direct cause of death than a visible fingerprint of a vascular system, and a patient, that has aged faster than the calendar suggests. The researchers caution that they could not calculate formal frailty indices in this retrospective cohort, so this hypothesis remains to be confirmed in prospective studies.
Notably, the tortuosity index did not predict periprocedural vascular complications in this cohort. Major vascular complications occurred in 16 percent of all patients and minor complications in 18.6 percent, with no significant difference between the low and high tortuosity groups. Puncture-related bleeding was the most frequent cause of access-site problems, followed by dissection or stenosis and pseudoaneurysm. The authors attribute this apparent disconnect to the dramatic technological evolution of TAVI over the study period, including lower-profile delivery systems, flexible introducer sheaths, ultrasound-guided puncture, and improved closure techniques, which have driven vascular complication rates down from roughly 15 percent in the earliest era to as low as 0.7 to 1.5 percent in contemporary practice.
The temporal dimension of the data adds nuance. Within the registry, 26 percent of major vascular complications occurred in patients treated before 2018, versus only 9.6 percent after that year. The statistical interaction between the tortuosity-mortality association and the year of treatment was significant, yet the index remained predictive of death even after adjustment for treatment year and period. This suggests that while better devices and growing operator experience have blunted the mechanical hazards of navigating twisted vessels, the prognostic signal embedded in arterial geometry persists, hinting at a biology that technology cannot yet override.
For clinicians, the practical message is that the tortuosity index, already validated for planning large-bore access in endovascular aneurysm repair, can be applied to TAVI patients using the same CT scans they already receive. A value above 1.5 may flag a higher-risk population deserving extra scrutiny during preprocedural planning, from ultrasound-guided access and high-support guidewires to straightening maneuvers and careful choice of access side. The study has limitations, including its single-center retrospective design, six-month follow-up, and the exclusion of roughly 40 percent of screened patients who lacked suitable CT imaging. Still, the idea that a number as mundane as a length ratio, calculated in seconds from an existing scan, could whisper something profound about a patient’s resilience is a compelling reminder that in medicine, sometimes the shape of things says as much as their substance.
Subject of Research: Association between peripheral vessel tortuosity index and six-month mortality after transfemoral transcatheter aortic valve implantation
Article Title: Peripheral vessel tortuosity index and prognosis in patients undergoing transcatheter aortic valve implantation
Article References: Alvarez-Covarrubias, H. A., Jurisic, M., Seguchi, M., Salzmann, C., Hug, K., Hübner, J., Starnecker, F., Syryca, F., Haug, F., Pellegrini, C., Rheude, T., Mayr, N. P., Cassese, S., Kastrati, A., Xhepa, E., & Joner, M. (2026). Peripheral vessel tortuosity index and prognosis in patients undergoing transcatheter aortic valve implantation. Clinical Research in Cardiology. https://doi.org/10.1007/s00392-026-03035-w
Image Credits: AI Generated
DOI: 10.1007/s00392-026-03035-w
Keywords: transcatheter aortic valve implantation, TAVI, tortuosity index, peripheral artery disease, computed tomography angiography, vascular complications, mortality, frailty, transfemoral access, iliac artery, aortic stenosis, cardiology
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Ophelia Keating. (October 1, 2026). Twisty Arteries May Signal Higher Death Risk After Heart Valve Procedure. Scienmag. https://scienmag.com/twisty-arteries-may-signal-higher-death-risk-after-heart-valve-procedure/
Ophelia Keating. “Twisty Arteries May Signal Higher Death Risk After Heart Valve Procedure.” Scienmag, 1 October 2026, https://scienmag.com/twisty-arteries-may-signal-higher-death-risk-after-heart-valve-procedure/. Accessed 1 October 2026.
Ophelia Keating. “Twisty Arteries May Signal Higher Death Risk After Heart Valve Procedure.” Scienmag. October 1, 2026. https://scienmag.com/twisty-arteries-may-signal-higher-death-risk-after-heart-valve-procedure/
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Tags: aortic stenosisarterial tortuosity and mortalitycardiologycomputed tomography angiographycomputed tomography angiography for vascular assessmentfemoral artery anatomy in cardiac proceduresfrailtygeometric measures in cardiovascular risk evaluationheart valve procedure risk factorsiliac arteryimpact of vessel curvature on TAVI outcomesmortalityperipheral artery anatomy and procedural successperipheral artery diseaserole of artery winding in surgical planningstructural heart intervention risk assessmentTAVItortuosity indextortuosity index as a predictor of post-procedure mortalitytranscatheter aortic valve implantationtranscatheter aortic valve implantation complicationstransfemoral accessvascular access challenges in transcatheter valve replacementvascular complications
