Moritz S. Bischoff

The Bentall procedure: Is it the gold standard? A series of 597 consecutive cases

OBJECTIVES We compared aortic root reconstructions using conduits with biological valves and mechanical valves. METHODS Of 597 patients (1995-2008), 307 (mean age 71 years [23-89 years]) had biological valves and 290 (mean age 51 years [21-82 years]) had mechanical valves. The subgroup of 242 patients aged 50 to 70 years included 133 with biological and 109 with mechanical valves. RESULTS Overall hospital mortality was 3.9% with biological valves (n = 15; elective: 3.7% [n = 10]) versus 2.8% with mechanical valves (n = 8; elective: 1.4% [n = 3]). In patients 50 to 70 years, age greater than 65 years (relative risk: 3.3 [P = .0001]), clot (relative risk: 2.5 [P = .05]), coronary artery disease (relative risk:3.5 [P < .0001]), and degenerative etiology (relative risk: 0.4 [P = .006]) were independent risk factors for long-term survival (after postoperative day 30); there was no difference in long-term survival between biological and mechanical valves (relative risk: 0.9 [P = .74]). The linearized rate for valve/ascending aorta reoperation was 0.86%/pt-y (2 in 2310 pt-y) after mechanical valves and 2.5%/pt-y (4 in 1586 pt-y) after Bentall procedures with the biological valve. CONCLUSIONS The choice of valve for aortic root reconstruction seems to have no influence on long-term outcome. Emergency operation and the presence of clot/atheroma have a significant impact on short-term outcome. Reoperation for either ascending aorta and/or aortic valve is low.

Staged Approach Prevents Spinal Cord Injury in Hybrid Surgical-Endovascular Thoracoabdominal Aortic Aneurysm Repair: An Experimental Model

BACKGROUND In a porcine model, we investigated the impact of sudden stent graft occlusion of thoracic intercostal arteries after open lumbar segmental artery (SA) ligation. METHODS After randomization into two groups, 20 juvenile Yorkshire pigs (27.1±0.6 kg) underwent open lumbar SA sacrifice (T13-L5) followed by endovascular coverage of all thoracic SAs (T4-T12) at 32°C, either in a single operation (group 1) or in two stages separated by seven days (group 2). Collateral network pressure (CNP) was monitored by catheterization of the SA L1, and postoperative hind limb function was assessed using a modified Tarlov score. RESULTS The CNP in group 1 decreased to 34% of baseline, whereas CNP after lumbar SA ligation in group 2 fell to 55% of baseline (74±2.4 to 25±3.6 mm Hg vs 74±4.5 to 41±5.5 mm Hg; p<0.0001). Subsequent thoracic stenting (group 2) led to another significant but milder drop (p=0.002 versus stage 1) from the restored CNP (71±4.2 to 54±4.9 mm Hg). Five of ten pigs in group 1 suffered paraplegia, in contrast to none in group 2 (median Tarlov score 6, vs 9; p=0.0031). Histopathologic analysis showed more severe ischemic damage to the lower thoracic (p=0.05) and lumbar spinal cord (p=0.002) in group 1. CONCLUSIONS These results underline the potential of the staged approach in hybrid procedures. Furthermore they highlight the need for established adjuncts for preventing paraplegia in hybrid and pure stent-graft protocols in which sudden occlusion of multiple SAs occurs.

When to operate on the bicuspid valve patient with a modestly dilated ascending aorta.

BACKGROUND Bicuspid aortic valves (BAV) are frequently associated with root/ascending aorta dilatation, but there is controversy regarding when to operate to prevent dissection of a dilated aorta associated with a well-functioning BAV. METHODS From 1988 through 2008, 158 patients (mean age: 56 ± 13.5 years) with a dilated ascending aorta (AA) and a well-functioning BAV were referred to our institution. All patients underwent computed tomographic (CT) scanning and digitization to calculate mean AA diameter. Forty-two patients underwent operation a median of 52 days after initial CT scan with a mean AA diameter of 5.6 ± 0.5 cm. One hundred sixteen patients (mean diameter 4.6 ± 0.5 cm) were enrolled in annual or semiannual surveillance. Seventy-one patients, 45 with 2 or more CT scans, are still under surveillance. RESULTS Average follow-up was 6.5 ± 4.1 years. Overall survival after the first encounter was 93% at 5 years and 85% at 10 years. A total of 87 of 158 patients had a Bentall or Yacoub procedure, with two hospital deaths (2.3%). Mean duration of surveillance in the 116 patients without immediate operation was 4.2 ± 2.9 years (481 patient-years). Average growth rate of the AA in patients with 2 scans or greater was 0.77 mm/year (p < 0.0001 versus normal population) with no significant impact of hypertension, sex, smoking or age. Forty-five of the 116 surveillance patients underwent operation after a mean of 3.4 ± 2.9 years (mean age 55 ± 14.7 years; mean AA diameter 4.9 ± 0.6 cm). Six patients died without surgery, median age 82 (range, 44 to 87) years, but none within one year of the last CT scan. CONCLUSIONS A consistent approach to patients with a well-functioning BAV and AA dilatation, recommending operation to those with an AA diameter greater than 5 cm and deferring operation in patients under surveillance in the absence of significant enlargement (>0.5 cm/year), resulted in overall survival equivalent to a normal age-matched and sex-matched population. Operation was necessary in approximately 10% of patients under surveillance each year.

Long-term outcome after aortic arch replacement with a trifurcated graft

OBJECTIVE We describe the long-term results of aortic arch replacement using a trifurcated graft, including an assessment of survival, neurologic complications, and graft patency. METHODS A retrospective review was conducted on data from 206 consecutive patients (125 male; median age, 67 years; range, 20-87 years) who had a trifurcated graft used for aortic arch replacement between September 1999 and September 2009. Seventy-four patients (35.9%) had chronic dissection, 68 patients (33.0%) had atherosclerotic aneurysms, and 39 patients (18.9%) had degenerative disease. Ninety-one patients (44.2%) had undergone previous cardiac surgery. RESULTS An elephant trunk was placed in 190 patients (92.2%) and completed in 101 patients (53.1%), with an interval of less than 365 days between stages in 94 of 101 patients. Hospital mortality was 6.8% (14/206). Adverse outcome (death/stroke within the first year postoperatively) occurred in 27.7% of patients (57/206; 50 deaths/7 strokes). Among 152 1-year survivors, the annual rates of transient ischemic attack and stroke were 0.85% and 1.1%, respectively. At 6 years, 75% of patients were still alive, compared with 92% in a matched New York State control population (P < .001). Follow-up computed tomography scans (189 studies in 176/206 patients [85.4%]) revealed 100% patency of the trifurcated graft limbs at a mean of 2.3 years. CONCLUSIONS Aortic arch replacement using a trifurcated graft is highly durable, with excellent patency in the branch grafts, and is associated with a low incidence of cerebral embolization. However, the long-term outcome in these patients is compromised by extensive comorbidities.

Measuring the collateral network pressure to minimize paraplegia risk in thoracoabdominal aneurysm resection

OBJECTIVE To minimize paraplegia during thoracoabdominal aortic aneurysm repair, the concept of the collateral network was developed. That is, spinal cord perfusion is provided by an interconnecting complex of vessels in the intraspinal, paraspinous, and epidural space and in the paravertebral muscles, including intercostal and lumbar segmental as well as subclavian and hypogastric arteries. METHODS Collateral network pressure was measured with a catheter in the distal end of a ligated segmental artery in pigs and human beings. RESULTS In the pig, collateral network pressure was 75% of the simultaneous mean aortic pressure. With complete segmental arterial ligation, it fell to 27% of baseline, recovering to 40% at 24 hours and 90% at 120 hours. Spinal cord injury occurred in approximately 50% of animals. When all segmental arteries were taken in 2 stages a week apart, collateral network pressure fell only to 50% to 70% of baseline, and spinal cord injury was rare. In human beings, baseline collateral network pressure also was 75% of mean aortic pressure, fell in proportion to the number of segmental arteries ligated, and began recovery within 24 hours. Collateral network pressure was lower with nonpulsatile distal bypass than with pulsatile perfusion. CONCLUSIONS After subtraction of a measure of spinal cord outflow pressure (cerebrospinal fluid pressure or central venous pressure), collateral network pressure provides a clinically useful estimate of spinal cord perfusion pressure.

Open Repair of Descending and Thoracoabdominal Aortic Aneurysms and Dissections in Patients Aged Younger Than 60 Years: Superior to Endovascular Repair?

BACKGROUND The best option for repair of descending thoracic and thoracoabdominal aortic aneurysms (TAAA)-whether open operation or stent grafting-is increasingly a subject of controversy. We examined the results of open surgical repair in patients aged 60 years or younger to assess the value of conventional repair in younger patients. METHODS From October 2002 to October 2010, 107 of 294 TAAA operations were in patients (75 men [70%]) aged a mean of 48 ± 9 years. Twelve patients (11%) had Marfan syndrome. Operations were elective in 101 (94%); previous aortic operations had been performed in 40 (37%). The most common indication for operation was chronic dissection, in 60 (56%); 5 (4.7%) had acute dissection, and rupture was present in 6 (5.6%). Descending repair was undertaken in 44 (41%), in 32 (73%) as an elephant trunk stage II. Deep hypothermic circulatory arrest was used in 46 (42.9%). Neurologic monitoring and cerebrospinal fluid drainage were routine. Median postoperative follow-up was 4.3 years (range, 2 days to 7.9 years). RESULTS Overall 30-day mortality was 4.7%. Stroke occurred in 4 patients (3.7%) and paraplegia in 1 (0.9%). The linearized rate for reoperation for TAAA was 0.22/100 patient-years (1 patient in 448.8 patient-years). Survival at 1, 5, and 8 years was 90.5%, 89.4% and 80.5%, respectively. During follow-up, 1 patient with Ehlers-Danlos died of aortic complications at 4.5 years. CONCLUSIONS Although direct comparison with stent grafting is limited by the diversity of patients and indications in published reports, our results suggest that open repair should be the modality of choice. Early mortality and neurologic complication rates are similar, if not superior, to endovascular repair for descending aortic and TAAAs. Open repair has proven durability and a very low rate of required reintervention, in contrast with endovascular repair.

Predicting the Risk for Acute Type B Aortic Dissection in Hypertensive Patients Using Anatomic Variables

OBJECTIVES This study sought to identify possible anatomic predictors of acute type B aortic dissection (AAD) in hypertensive patients using multidetector computed tomography angiography (CTA). BACKGROUND Although hypertension remains one of the most significant risk factors for AAD development, it is unlikely to be the only risk factor for AAD. Few studies have assessed anatomical predictors of AAD development. METHODS CTA of normotensive patients without AAD (group 1, n = 35), hypertensive patients without AAD (group 2, n = 37), and hypertensive patients with AAD (group 3, n = 37) were compared. The length, diameter, volume, and tortuosity of the aorta as well as arch vessel angulation were measured for each patient and normalized to group 1 averages. Stepwise logistic regression identified significant anatomical associations; the model was validated based on 1,000 bootstrapped samples. RESULTS The demographics of the groups were similar. The length of the proximal and entire aorta, the diameters in the proximal ascending aorta and aortic arch, and the aortic volumes were all greater (p < 0.0001, p = 0.0064 for ascending aortic diameter) in group 3 than in groups 1 and 2, as was entire aortic tortuosity (p < 0.0001). An AAD risk model was developed based on aortic arch diameter, length from the aortic root to the iliac bifurcation, and angulation of the brachiocephalic artery origin from the aorta. The bootstrap estimate of the area under the receiver operating curve was 0.974. CONCLUSIONS Enlargement of the ascending aorta and aortic arch and increased aortic tortuosity reflect an aortopathy which enhances the probability of AAD. A model based on 3 anatomical variables demonstrates significant associations with AAD: it may allow identification by aortic imaging of the hypertensive patient most at risk, and permit implementation of aggressive medical management and consideration of pre-emptive surgery to prevent dissection.

Early experience with automatic pressure-controlled cerebrospinal fluid drainage during thoracic endovascular aortic repair.

Purpose: To report initial experience with automatic pressure-controlled cerebrospinal fluid drainage (CSFD) during thoracic endovascular aortic repair (TEVAR). Methods: A prospective nonrandomized study enrolled 30 consecutive patients (median age 68 years, range 42–89; 18 men) who underwent TEVAR between March 2012 and July 2013 and were considered to be at high risk for postoperative spinal cord ischemia (SCI), fulfilling 2 of the following criteria: stent-graft length >20 cm, left subclavian artery coverage, and previous infrarenal aortic repair. All patients received perioperative CSFD via the LiquoGuard system. The protocol aimed for a CSF pressure of 10 mm Hg and duration of CSFD of 3 or 7 days in asymptomatic or symptomatic patients, respectively. Muscle strength of the lower extremities was assessed with the Oxford muscle strength grading scale. Results: Completion of the CSFD protocol was achieved in 26 (87%) of 30 patients. CSFD was prematurely stopped due to catheter dislocation in 1 patient and bloody spinal fluid in 3 patients. CSFD was performed for a median of 3 days (range 1–7). Median total CSFD volume was 714 mL (range 13–2369), with a median 192 mL drained per 24 hours. The SCI rate was 3% (1/30). CSFD-related complications were observed in 33% of the patients: 1 fatal intracranial hemorrhage, 3 bloody spinal fluid episodes, 3 persistent CSF leaks requiring epidural blood patch, and 3 post lumbar puncture headaches. Mortality during a median follow-up of 16 months (range 10–25) was 3% (1/30). Conclusion: Prophylactic CSFD was associated with a low SCI rate in a high-risk patient collective undergoing TEVAR. Monitoring and drainage by an automatic modus was feasible, reproducible, and reliable but associated with relevant drainage-associated complications.

Penetrating aortic ulcer

In addition to classic aortic dissection and intramural hematoma, acute aortic syndrome also includes penetrating aortic ulcers (PAU). The recent advent of highly detailed axial imaging allows closer assessment of PAU and its pathophysiology. However, there is still ongoing discussion about the natural history of the disease, leading to challenging questions concerning the optimal treatment strategy, particularly in asymptomatic patients. In this review, current indications for treatment, with an emphasis on PAU repair in the endovascular era, are discussed.ZusammenfassungDas penetrierende Aortenulkus (PAU) zählt mit dem intramuralen Hämatom und der klassischen Aortendissektion zur Entität des akuten Aortensyndroms. Trotz moderner Schnittbildgebung, welche eine hochauflösende Darstellung dieser Aortenpathologie erlaubt, sind die dem PAU zugrunde liegenden pathophysiologischen Zusammenhänge noch nicht vollständig geklärt. Aufgrund der unzureichenden Datenlage bezüglich des natürlichen Verlaufs der Erkrankung bestehen nach wie vor offene Fragen hinsichtlich der optimalen Behandlungsstrategie. Dies trifft insbesondere bei klinisch asymptomatischen Patienten zu. In der vorliegenden Übersichtsarbeit werden aktuelle Behandlungsindikationen und Therapieansätze bei PAU mit dem Schwerpunkt der endovaskulären Versorgung diskutiert.

Penetrating aortic ulcer: defining risks and therapeutic strategies.

In addition to classic aortic dissection and intramural hematoma, acute aortic syndrome also includes penetrating aortic ulcers (PAU). The recent advent of highly detailed axial imaging allows closer assessment of PAU and its pathophysiology. However, there is still ongoing discussion about the natural history of the disease, leading to challenging questions concerning the optimal treatment strategy, particularly in asymptomatic patients. In this review, current indications for treatment, with an emphasis on PAU repair in the endovascular era, are discussed.ZusammenfassungDas penetrierende Aortenulkus (PAU) zählt mit dem intramuralen Hämatom und der klassischen Aortendissektion zur Entität des akuten Aortensyndroms. Trotz moderner Schnittbildgebung, welche eine hochauflösende Darstellung dieser Aortenpathologie erlaubt, sind die dem PAU zugrunde liegenden pathophysiologischen Zusammenhänge noch nicht vollständig geklärt. Aufgrund der unzureichenden Datenlage bezüglich des natürlichen Verlaufs der Erkrankung bestehen nach wie vor offene Fragen hinsichtlich der optimalen Behandlungsstrategie. Dies trifft insbesondere bei klinisch asymptomatischen Patienten zu. In der vorliegenden Übersichtsarbeit werden aktuelle Behandlungsindikationen und Therapieansätze bei PAU mit dem Schwerpunkt der endovaskulären Versorgung diskutiert.