Transcaval Access and Closure for Transcatheter Aortic Valve Replacement: A Prospective Investigation

Abstract

Background: Transcaval access may enable fully percutaneous transcatheter aortic valve replacement (TAVR) without the hazards and discomfort of transthoracic (transapical or transaortic) access.

Objectives: The authors performed a prospective, independently adjudicated, multicenter, single-arm trial of transcaval access for TAVR in patients who were ineligible for femoral artery access and had high or prohibitive risk of complications from transthoracic access.

Methods: A total of 100 patients underwent attempted percutaneous transcaval access to the abdominal aorta by electrifying a caval guidewire and advancing it into a pre-positioned aortic snare. After exchanging for a rigid guidewire, conventional TAVR was performed through transcaval introducer sheaths. Transcaval access ports were closed with nitinol cardiac occluders. A core laboratory analyzed pre-discharge and 30-day abdominal computed tomograms. The Society of Thoracic Surgeons predicted risk of mortality was 9.6 ± 6.3%.

Results: Transcaval access was successful in 99 of 100 patients. Device success (access and closure with a nitinol cardiac occluder without death or emergency surgical rescue) occurred 98 of 99 patients; 1 subject had closure with a covered stent. Inpatient survival was 96%, and 30-day survival was 92%. Second Valve Academic Research Consortium (VARC-2) life-threatening bleeding and modified VARC-2 major vascular complications possibly related to transcaval access were 7% and 13%, respectively. Median length of stay was 4 days (range 2 to 6 days). There were no vascular complications after discharge.

Conclusions: Transcaval access enabled TAVR in patients who were not good candidates for transthoracic access. Bleeding and vascular complications, using permeable nitinol cardiac occluders to close the access ports, were common but acceptable in this high-risk cohort. Transcaval access should be investigated in patients who are eligible for transthoracic access. Purpose-built closure devices are in development that may simplify the procedure and reduce bleeding. (Transcaval Access for Transcatheter Aortic Valve Replacement in People With No Good Options for Aortic Access; NCT02280824).

Keywords: caval-aortic access; nontransfemoral access; structural heart disease; transcatheter aortic valve replacement; transcaval; vascular access.

Figure 2. Proposed mechanism of hemodynamic stability after transcaval access using permeable nitinol occluder devices

Higher pressure in the relatively confined retroperitoneal space exceeds venous pressure (Inset) and causes aortic blood to return to the venous circulation through a nearby hole in the IVC (inset). The result is aortocaval fistula rather than hemodynamic collapse. Courtesy of A Hoofring, NIH Medical Arts Branch.

Figure 3. Crossing equipment

A. Coaxial crossing system consisting of (1) 0.014″ guidewire inside of a (2) Piggyback 0.035″ wire convertor insider of a (3) braided microcatheter, inside of a (4) 55cm guiding catheter. B. An electrosurgery pencil (5) is connected to the back end of the 0.014″ guidewire (6) using a hemostatic forceps (7).

Figure 4. A representative transcaval TAVR procedure

(A–E) A suitable target (yellow arrow) is identified on CT and displaced in axial (C) reconstruction to show crossing point, sagittal reconstruction (D) to show lumbar level, and coronal thick-slab projection to simulate fluoroscopy (E). Under fluoroscopy, the transvenous crossing catheter is aligned with the aortic snare in a lateral projection (F), and the guidewire is electrified during advancement into the aorta (G) and then snared (H) and exchanged for a stiff guidewire. The THV sheath is advanced from the femoral vein into the aorta (I). After TAVR, a nitinol cardiac occluder device is positioned across the aortic wall (J–L). In this case, completion angiography shows complete occlusion of the aorto-caval fistula (M). Predischarge CT (N–O) shows the device in position with a small retroperitoneal hematoma and an occluded tract.

Figure 5. Unconstrained aorto-caval shunt after inadvertent pull-through of a closure device

A: This angiogram was performed while preparing a new closure device. The blood pressure was not changed. The arrow points to the unrepaired aorto-caval fistula. B: A fistula persists on the completion angiogram after a closure device was implanted. C–D: On pre-discharge CT, there is no retroperitoneal hematoma, and the fistula is reduced but persistent. It is occluded on follow-up CT (E–F)

Central Illustration. Transcaval access technique

Transcaval access is obtained over an electrified guidewire directed from the IVC towards a snare in the abdominal aorta (A). After delivering a microcatheter to exchange for a stiff guidewire (B), the transcatheter heart valve introducer sheath is advanced from the femoral vein into the abdominal aorta for conventional transfemoral retrograde TAVR (C). The aorto-caval access site is closed with a nitinol cardiac occluder (D). Courtesy of A Hoofring, NIH Medical Arts Branch.