Transseptal Guidewire Stabilization Facilitates Stent-Graft Deployment for Persistent Proximal Ascending Aortic Dissection

Endovascular ascending aortic repair in type A dissection: A systematic review

PURPOSE

Up to 10% of acute type A aortic dissection (TAAD) patients are deemed unfit for open surgical repair, exposing these patients to high mortality rates. In recent years, thoracic endovascular aortic repair has proven to be a promising alternative treatment modality in specific cases. This study presents a comprehensive overview of the current state of catheter-based interventions in the setting of primary TAAD.

METHODS

A literature search was conducted, using MEDLINE and PubMed databases according to PRISMA guidelines, updated until January 2020. Articles were selected if they reported on the endovascular repair of DeBakey Type I and II aortic dissections. The exclusion criteria were retrograde type A dissection, hybrid procedures, and combined outcome reporting of mixed aortic pathologies (e.g., pseudoaneurysm and intramural hematoma).

RESULTS

A total of 31 articles, out of which 19 were case reports and 12 case series, describing a total of 92 patients, were included. The median follow-up was 6 months for case reports and the average follow-up was 14 months for case series. Overall technical success was 95.6% and 30-day mortality of 9%. Stroke and early endoleak rates were 6% and 18%, respectively. Reintervention was required in 14 patients (15%).

CONCLUSION

This review not only demonstrates that endovascular repair in the setting of isolated TAAD is feasible with acceptable outcomes at short-term follow-up, but also underlines a lack of mid-late outcomes and reporting consistency. Studies with longer follow-up and careful consideration of patient selection are required before endovascular interventions can be widely introduced.

Computed tomography-based study exploring the feasibility of endovascular treatment of type A aortic dissection in the Chinese population

PURPOSE

To characterize type A aortic dissection (TAAD) in the Chinese population using high-resolution computed tomography (CT) and explore potential candidacy for endovascular repair of TAAD.

METHODS

The imaging studies and medical records of all 302 patients presenting with TAAD at two Chinese hospitals from 2010 to 2013 were reviewed. Of these, 221 patients were excluded because of missing/inadequate preoperative CT scans. The remaining 91 patients (64 men; mean age 51.1±7.5 years) had CT data adequate to assess anatomical suitability for endovascular treatment. Entry tears were identified using multiplanar reconstructions, while morphological measurements were based on a centerline of flow (CLF) technique. Suitability for endovascular treatment was based on a proximal landing zone ≥20 mm long, a true lumen aortic diameter ≤38 mm, and a total aortic diameter ≤46 mm; no coronary bypass grafts originating from the ascending aorta; no malfunctioning aortic valve; and good cerebral and cardiac perfusion.

RESULTS

In the 91 patients, the precise location of the primary proximal entry tear could be identified in only 34 (37.4%) patients; in these patients, the identifiable intimal tears were located 36.4±41.0 mm distal to the closest coronary artery. The CLF was successfully generated in the CT scans of all patients; the mean lumen and total aortic lumen diameters at the entry tear level were 37.6±6.3 and 44.3±13.3 mm, respectively. Based on the CT measurements, stent-graft repair would have been anatomically feasible in 35 (38.5%) patients. No proximal landing zone (n=23), large aortic diameter (n=15), abnormal aortic valve (n=10), previous coronary bypass graft surgery (n=5), and poor cerebral and cardiac perfusion (n=3) were obstacles that affected the suitability for this treatment.

CONCLUSION

Based on high-resolution CT scans, our pilot study suggested that 38% of Chinese patients with TAAD could potentially be treated by stent-grafting based on the anatomical characteristics of the proximal dissection.

High-dose adenosine-induced asystole assisting accurate deployment of thoracic stent grafts in conscious patients

Adenosine has been used to induce asystole and assist deployment of endoluminal grafts. However, application of high-dose adenosine in conscious patients has not been described. In this prospective study, we administered high-dose adenosine in patients undergoing thoracic stent grafting. Asystole duration in relationship to the dosage of adenosine, safety, and side effect profiles was investigated. All patients who underwent thoracic stent grafting between 1998 and 2006 were the potential study subjects. They received monitored anesthesia care and local anesthesia unless contraindicated. Adenosine was given via rapid intravenous bolus immediately prior to the deployment of the stent graft. Every patient received a dose of 36 mg. If needed, a second dose of 18 mg was given. Duration of asystole was recorded after each administration. Patients' vital signs before and after administration were also documented. Side effect profiles were collected intra- and postoperatively. A total of 46 patients received adenosine (34 men, 12 women). Mean age was 60.4 +/- 17.5 years. American Society of Anesthesiologists scores were II in one patient (2%), III in six patients (13%), and IV in 39 patients (85%). Eighteen patients received a single dose of 36 mg adenosine, 15 were given a second dose of 18 mg, and 13 received nonstandard dosages. Asystole durations were 18.8 +/- 8.8 and 11.6 +/- 5.5 sec for 36 and 18 mg, respectively. Technical success was achieved in all cases. The differences achieved statistical significance (p = 0.0009). There were no severe cardiac or pulmonary complications. High-dose adenosine can be given safely in conscious patients. The dose-response was predictable and reproducible. The dosages used in our study induce sufficient duration of asystole, which ensured accurate deployment of thoracic stent grafts.

Partial inflow occlusion facilitates accurate deployment of thoracic aortic endografts

PURPOSE

To present a maneuver consisting of temporary blockage of the venous return to the heart for accurate deployment of thoracic aortic endoprostheses.

TECHNIQUE

During endovascular repairs in the thoracic aorta, an occluding balloon was introduced through the femoral vein into the right atrium under transesophageal echocardiographic control. The venous return through the inferior vena cava was temporarily blocked to reduce aortic flow during device deployment. The technique was applied in 21 patients with various lesions of the thoracic aorta. Partial inflow occlusion resulted in a mean systolic pressure of 49+/-6 mmHg and lasted for 52+/-14 seconds. Cardiac function was comparable to the preocclusion state, and no arrhythmias or ischemic events were encountered. In 7 procedures, inotropic or vasoconstrictor support was necessary after deployment. No complications related to the venous system were observed. The endoprostheses were precisely deployed at the target site in all patients.

CONCLUSIONS

The force of aortic flow often impairs precise deployment of thoracic endoprostheses, resulting in distal displacement. Partial inflow occlusion provides precise control over the extent and duration of the hypotensive period, allowing accurate deployment of thoracic endoprostheses.