Acute aortic regurgitation secondary to aortic dissection. Surgical management without valve replacement

Hassan Najafi, May 22, 1930-May 20, 2017

Dr Hassan Najafi, an immigrant from Iran who became the 18th president of The Society of Thoracic Surgeons, died on May 20, 2017. He had also served as chair of the American Board of Thoracic Surgery and the Residency Review Committee for Thoracic Surgery, and was a founding member and first president of the Thoracic Surgery Directors Association. A superb technical surgeon, educator, and investigator, Dr Najafi led the Department of Cardiovascular and Thoracic Surgery at Rush University Medical Center for 25 years. Refined and charismatic, he was wholly devoted to his patients, family, trainees, colleagues, and our profession.

Total aortic repair: the new paradigm in the treatment of acute type A aortic dissection

The surgical management of acute type A aortic dissection (ATAAD) is in a period of rapid evolution. Understanding the complex physiology and anatomy of both acute and chronic dissection has been enhanced by the ready availability of state of the art imaging techniques. Technical advances in the intraoperative monitoring of organ perfusion, together with adjuncts to limit organ injury and increasing sophistication in open and endovascular surgery have led to a major reduction in both perioperative morbidity and mortality. In many centers, there has been a transition in mindset and surgical approach away from a purely central aortic operation focusing on the ascending aorta and a 'live to fight another day' philosophy. The current more global perspective recognizes the importance of aortic valve function, malperfusion, false lumen (FL) patency and the potential for future complex aneurysm development. The time is now right to transition into the next phase of sophistication in the management of ATAAD with the aim of achieving not only a safe acute operation, but to either entirely prevent chronic complications or to greatly simplify their management by the creation of an anatomical situation that facilitates future endovascular intervention in place of complex re-do surgery. We present our view on the evolution of surgery for ATAAD leading to our current technique of Branch First Arch replacement and Total Aortic Repair, which not only provides a safe immediate operation, but also offers the hope of a simplified future management if not a total cure for the pathology.

Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair

OBJECTIVES

The purpose of this study was to use transesophageal echocardiography (TEE) to define the mechanisms of aortic regurgitation (AR) in acute type A aortic dissection so as to assist the surgeon in identifying patients with mechanisms of AR suitable for valve preservation.

BACKGROUND

Significant AR frequently complicates acute type A aortic dissection necessitating either aortic valve repair or replacement at the time of aortic surgery. Although direct surgical inspection can identify intrinsically normal leaflets suitable for repair, it is preferable for the surgeon to correlate aortic valve function with the anatomy prior to thoracotomy.

METHODS

We studied 50 consecutive patients with acute type A aortic dissection in whom preoperative TEE findings were considered by the surgeons in planning aortic valve surgery. Six patients did not undergo surgery (noncandidacy or refusal) and one patient had had a prior aortic valve replacement and therefore was excluded from the analysis.

RESULTS

Twenty-seven patients had no or minimal AR and 22 had moderate or severe AR. In all, there were 16 with intrinsically normal leaflets who had AR due to one or more correctable aortic valve lesion: incomplete leaflet closure due to leaflet tethering in a dilated aortic root in 7; leaflet prolapse due to disrupted leaflet attachments in 8; and dissection flap prolapse through the aortic valve orifice in 5. Of these 16 patients, 15 had successful aortic valve repair whereas just 1 underwent aortic valve replacement after a complicated intraoperative course (unrelated to the aortic valve). Nine patients underwent aortic valve replacement for nonrepairable abnormalities, including Marfan's syndrome in four, bicuspid aortic valve in four, and aortitis in one. In patients undergoing aortic valve repair, follow-up transthoracic echocardiography at a median of three months revealed no or minimal residual AR, and clinical follow-up at a median of 23 months showed that none required aortic valve replacement.

CONCLUSIONS

When significant AR complicates acute type A aortic dissection, TEE can define the severity and mechanisms of AR and can assist the surgeon in identifying patients in whom valve repair is likely to be successful.

Twenty-year follow-up of acute type a dissection: the incidence and extent of distal aortic disease using magnetic resonance imaging

A persistent distal false lumen (PDFL) after surgical repair of type A aortic dissection is the most important factor in determining long-term survival. It has been suggested that changes in surgical technique reduce the incidence of distal false lumen. We report the findings of a 20-year follow-up (mean 5.2 years) on 87 patients who have undergone surgical repair of type A aortic dissection with all survivors undergoing magnetic resonance (MR) scanning of the entire aorta. Early mortality was 27.5%, and actuarial 5-, 10-, and 15-year survival was 65%, 28% and 20% respectively. Early mortality had decreased to 18% in the last 5 years. The most common cause of late death was related to distal aortic disease, accounting for 47% of all late deaths with a peak incidence at 7-10 years after surgery. The incidence of PDFL in survivors was 72%, despite the fact that 82% of all intimal tears were resected at time of operation. Incidence was not affected by extension of the repair into the aortic arch nor by the use of the open technique or Gelatin-Resorcine-Formal tissue glue. In patients with a distal false lumen 6% had reached a maximum aortic diameter of 6 cm in at least one plane on MR scanning and 25% had reached 5 cm. We conclude that if dissection has extended beyond the arch at time of presentation then the choice of surgical technique does not prevent the persistance of a distal false lumen. MR scanning gives ideal anatomical and functional assessment of distal aortic disease and provides the surgeon with all the necessary information to plan the timing and indications for further surgery.

Selectivity in aortic root reconstruction

Anatomical variations in aortic root pathology, including combinations of dissection, aneurysmal dilatation, annuloaortic ectasia, and valve disease, defy standardized repair and mandate application of various surgical reconstructions. To examine these techniques, and their influence on morbidity and mortality, we reviewed 53 consecutive patients undergoing aortic root procedures. Thirty-two patients underwent total root reconstruction. Of these, 21 underwent Bentall procedures, 9 had a modification thereof, and 2 underwent a Cabrol reconstruction. Less extensive pathology was corrected in 21 patients with a partial root reconstruction. These included aortic valve replacement (AVR) and a separate tube graft in 14 patients, AVR and primary aortic repair +/- wrapping in 4 individuals, and AVR and patch aortic root enlargement in 3 patients. Mean age was 53.2 years (range 20 to 79). Nearly 20% had undergone previous cardiac surgery and 7.5% were emergencies. Early mortality was 4%. Complications included dysrhythmias (48%), myocardial infarction (4%), stroke (4%), pneumonia (14%), and pancreatitis (2%). There were no reoperations for bleeding. Three late complications, one pseudoaneurysm and two perivalvular leaks, were successfully repaired. Late deaths (13.7%) were caused by congestive heart failure (3), myocardial infarction (MI) (1), cancer (1), stroke (1), and accidental fall (1). Kaplan-Meier analysis reveals 1-, 5-, and 10-year survivals of 98%, 81%, and 66%. Survival and mortality data did not differ between groups, and except for the incidence of atrial dysrhythmias, complication rates also were not significantly different. This series illustrates the need for and the successful application of a selective approach to aortic root reconstruction.

Primary anastomosis for acute ascending aortic dissection

Intimal tear resection and primary anastomosis of the aorta were used for the treatment of eight patients with DeBakey I and II type acute aortic dissection. Five patients were of DeBakey I type, and three patients were of the II type. Moderate or severe aortic regurgitation (AR) was observed in six of eight patients. The site of the intimal tear was diagnosed by intraoperative echocardiography, and the adventitia corresponding to the intimal tear was transversely opened under total cardiopulmonary bypass. While resuspension of the aortic valve was performed on only one of six patients, AR disappeared in four, postoperatively. Two of eight patients died early postoperatively. The cause of death was postoperative cardiac tamponade in one patient and cerebral herniation in the remaining one. The other six patients have been observed for a mean period of 27 months. There is no late death, and they show no dilatation of the aortic root and deterioration of AR. We believe that this operative method is a simple and safe emergency procedure for DeBakey I and II type acute aortic dissection.

Primary repair of acute ascending aortic dissection

Primary repair of acute ascending aortic dissection was performed in 14 patients. Repair included resection of the intimal tear where applicable, a circumferential suture line in the ascending aorta at the site of the tear, and wrapping of the intrapericardial ascending aorta with Teflon felt to contain the distal residual false channel. The aortic valve was resuspended in 6 patients. The single operative death was unrelated to the method of repair. Two late deaths at 4 and 6 years were due to preexisting multisystem disease. In 1 patient, new aortic insufficiency with an isolated aneurysm of the noncoronary sinus of Valsalva developed at 26 months, and was repaired successfully at another institution. These results compare favorably with those reported by others employing more extensive surgical procedures for repair of acute ascending aortic dissection.

Acute dissections of the aorta. Current surgical treatment

Tremendous progress has been made in the treatment of acute aortic dissections as a result of advances in surgical, medical, and diagnostic modalities. Rapid clinical diagnosis should be followed by aggressive monitoring, pharmacologic manipulation, and definitive elucidation of the anatomy of the disorder. Ultrasonography and CT scanning may provide valuable information on the anatomy of the dissection, but contrast arteriography remains the preferred method for demonstrating the anatomy. Surgical correction is now recommended for both type A and type B dissections during the acute stage. The exact approach is dictated by the location of the intimal tear and the extent of the dissection. The complexity of the operation may extend from interposing an intraluminal graft to full cardiopulmonary bypass with profound hypothermia, circulatory arrest, and replacement of the ascending aorta, aortic arch, or aortic valve apparatus. The rapid advancement of management techniques for acute aortic dissections now offers patients a reasonable expectation of survival without complications. Future improvements in early, noninvasive, and rapid diagnostic methods, as well as increased utilization of invasive monitoring and nonporous graft materials, promise to increase survival for a patient afflicted with acute aortic dissection.

Surgical treatment of aneurysms of the ascending aorta associated with severe aortic regurgitation

From January 1979 to June 1982 31 patients have had simultaneous ascending aortic aneurysm repair and aortic valve replacement. Fifteen patients (group 1) received a composite graft; seven patients (group 2) had separate aortic valve and supracoronary ascending aorta prostheses; and nine patients (group 3) had aortic valve replacement and "tailoring" of the ascending aorta. The mean age was 50 (SD 14) years. Nine patients had acute dissection, five with the coronary ostia affected. Emergency surgery was performed in 10 cases. There were six early deaths (19.4%), none of them due to technical complications during surgery. The mortality rate was 56% for patients with acute dissection operated on as an emergency and 4.5% for patients having elective operations. Appreciable haemorrhage occurred in four patients (12.9%). No neurological complications occurred. There was one late death. The survivors were followed up for one to four years. There was one case of recurrence of aneurysm. No ischaemic complications resulted from coronary reimplantation. There were no significant differences in the results of the three groups. Simultaneous ascending aortic aneurysm repair and aortic valve replacement can be accomplished with an acceptable mortality rate and little morbidity.

Technical options in repairing the diseased ascending aorta with aortic valve involvement

Operative repair of the diseased ascending aorta with aortic valve involvement consists of replacement of the ascending aorta and the aortic valve plus reconstitution of coronary arterial flow. Two basic techniques are presently available. The conventional technique involves separate replacement of the aorta and valve above and below a small segment of retained aorta including the coronary orifices. The second method consists of replacement of the entire ascending aorta and aortic valve with reconstitution of coronary flow by approximation of the coronary orifices to the Dacron conduit or with saphenous vein bypasses. Each method has its merits depending on the exact pathological anatomy encountered near the coronary orifices. Other pathological variables exist that demand additional intraoperative choices in technique. The present report details the operative repair of this lesion and outlines the technical options available for solution of the various problems encountered.

The effectiveness of surgical treatment of acute aortic dissection

Ten consecutive patients have undergone operative repair of acute aortic dissection at St. Thomas Hospital in the last three years. Two died. To assess the status of the residual aorta, all 8 survivors were evaluated by postoperative aortography. Only the patient with a clotted dissection on preoperative study showed no residual dissection of the distal aorta. Analysis of postoperative aortograms suggests that the original dissection reentry points become sites of inflow following removal of the original intimal tear. No death resulted from these residual abnormalities. Retrograde dissection and aortic insufficiency were obliterated. The major sites of aortic rupture were removed. It is concluded that surgical therapy for acute aortic dissection is effective in that it avoids the major sources of mortality. The resultant surviving population must be carefully observed in view of the high frequency of residual aortic abnormality.