Management of Acute Aortic Dissection Type A

1. Interhospital conference ครั้งที่ 29 Acute Aortic Syndrome Management of Acute Aortic Dissection Type A นพ.ณัฐพล อารยวุฒิกุล หน่วยศัลยกรรมหัวใจทรวงอกและหลอดเลือด โรงพยาบาลศูนย์ลำปาง

2. King George 2 of Great Britain died(october 25,1760)while training on the commode and was the first well documented case of an aortic dissection.

3. Historical Note • Recognized since 16 th century. • Lannaec(French physician) introduced term Dissection aneurysm in 1819.

4. Historical Note • First successful outcome of modern treatment of aortic dissection was attributed to Dr. DeBakey in his report, 1955 and later he devised a classification that is widely used today as Debakey classification.

5. Historical Note • Technological and technical improvements follow: • Cardiopulmonary bypass circuit. • Synthetic placements. • Hypothermic circulatory arrest in 1960s to 1975( Barnard , Schrire, Borst and Griepp with colleaques) • Open distal anastomosis technique by Livesay in 1982. • Bioglue has been approved by US FDA to strengthen the disrupted layer.

10. Classifications • De Bakey • Type 1 = ascending aorta, aortic arch, descending aorta • Type 2 = ascending aorta only • Type 3 = descending aorta distal to left subclavian artery • Type 3a= limit to descending thoracic aorta • Type 3b= extend below diaphragm • Stanford (most common) • Type A = involves ascending aorta • Type B = no ascending aorta, distal

11. Type of Aortic Dissection • The proportion of patients with various types depend on the nature of series reported • Type one and two (or type A) comprised 35% of cases (from Debakey series). • From clinical and autopsy series, acute dissections involved the ascending aorta was found in 62% to 85% of cases.

12. Intramural Hematoma Intramural hematoma involving the ascending aorta Should be treated like an acute type A aortic dissection Aortic IMH is considered a precursor to classic aortic dissection T sai TT. Acute aortic syndromes. Circulation 2005

13. Natural history • 50% are dead within 48 hrs • Long term survival in untreated type A dissection: • More than 25% died in 24 hrs. • More than 50% died in the first week. • More than 75% died in 1 month. • More than 90% died in 1 year.

15. Mode of Death • Most patients who die acutely succumb from false channel rupture with hemopericardium, hemomidiastinum or hemothorax. • Death later can result from delayed rupture or organ dysfunction secondary to arterial occlusions.

16. Course after surviving acute dissection • False channel usually and gradually become aneurysmal, and then ruptures months or years after the acute episode. • A new dissection or redissection may occur.

17. Presentation • 40% die immediately • 30% who present to hospital are first thought to have another diagnosis • Most common symptom: • Severe, unrelenting chest pain • Described as ripping or tearing/ sharp pain • Patients look agony ( nausea, vomiting, diaphoresis) • Symptoms of tamponade • AR murmur • Abnormal pulse exam • Abnormal neurologic exam

18. Exam • Can be normal • Hypertension ( normal or low does not exclude dissection) • If subclavian artery involved = asymmetri pulses or BP ( > 20 mmHg difference between arms) • If proximal dissection • Shock • New murmur of AR/ HEART FAILURE

20. Initial diagnostic steps and decisions • EKG • Normal in 1/3 ( in coronary involement) • ST-T change

21. Initial diagnostic steps and decisions • TTE • Useful screening tool in identifying type A dissection • Limited visualization to distal ascending, transverse and descending • Paramount in assessing cpx. AR/tamponade/EF • TEE • TEE with color flow imaging is considered as the most useful and accurate diagnostic technique

22. Initial diagnostic steps and decisions • Coronary angiogram • selective coronary angiogram to identify involvement of the coronary arties is not indicated.(TEE, direct examination of coronary arteries after the aorta was opened) • Use of coronary angiogram to detect atherosclerotic disease in patients who are to undergo surgical treatment of acute dissection is arguable.

23. Aortic dissection diagnostic studies • Helical CT sense-93% spec-100% • Most frequently used • MRI sens-98% spec 98% • Presence of artifact in nearly 60% of cases • Echo TTE sense-59-85%, spec 63-96% • Echo TEE sense-98%, spec 98% • IVUS • Particulary useful for delineating the proximal and distal extent • Coronary angiography • Controversial

25. What is the optimal treatment

26. General principles • Acute aortic dissections involving the ascending aorta are considered surgical emergencies.

27. General principles • In contrast, dissections confined to the descending aorta are treated medically unless there is/are complications.

28. Initial medical Therapy • The primary objective is to normalize pressure and to reduce the force of left ventricular ejection (dP/dt).

31. Initial medical Therapy • If beta-blockers alone do not control blood pressure, vasodilators such as NTP ( the first vasodilator of choice) • Good pain control as morphine. • Volume titration. • Intubation early.

32. Hypotensive patients • Cardiac tamponade • Severe AR • True-lumen obstruction • Acute MI • Contained rupture of the false lumen into pleural space or mediastinum • ### every scenarios mandate immediate operative intervention####

33. Pericardiocentesis • Associated with recurrent pericardial bleeding and associated mortality • Several articles from Asian literature suggest that it may be safe in the setting of acute type A IMH • Except for cases who cannot survive until surgery, pericardiocentesis can be done by withdrawing just enough fluid to restore perfusion

34. Purpose of Surgical Treatment • To treat or prevent the common and lethal complications such as • Aortic rupture • Stroke • Visceral ischemia • Cardiac tamponade • Circulatory failure

35. Principle of repair • Excision of intimal tear • Obliteration of entry into FL • Reconstitution of aorta with interposition graft +/- coronary reimplantations • Restoration of aortic valve incompetence • Valve resuspension • Aortic valve replacement • Aortic root replacement

36. European Society of Cardiology task force on acute type A Dissection

37. Operative mortality • Operative mortality in experienced centers with large surgical series varies widely between 15%-35%, still below the 50% mortality with medical therapy

40. General considerations • Establishing CPB in traditional way. • Rt radial a. line/ femoral a. line opposite to cannulation site. • Routine TEE • If FEM-FEM bypass is chosen. • CFA with the most normal pulse • CFV on the right should be used ( easily positioned to RA )

41. General considerations • If circulatory arrest is needed, the core temp should be lower to less than 20 celsius with good LV venting. • If aortic cross clamping is planning, clamp should be placed several centimeters proximal to innominate artery.

42. AHA Guidelines 2010 • Treatment acute type A Dissection • All of aneurysmal aorta and the proximal extent of the dissection should be resected. • A partially dissected root may be repaired by aortic valve resuspension.

43. AHA Guidelines 2010 • Patients with Type A Dissection • Extensive aortic root dissection should be treated with aortic root replacement with a composite graft or with a valve sparing root replacement. • In DeBekey Type 2 dissection the entire dissected aorta should be replaced

44. Arterial Access for Cannulation • Possible cannulationtion sites • Femoral cannulation • Right axillary artery • Left common carotid artery • Direct cannulation of aorta by TEE control • Direct cannulation( cut open under visual control) • Transapical cannulation.

45. AxillaryCannulation

46. Axillary Cannulation Advantages Disadvantages • Antegrade perfusion. • No manipulation of the ascending aorta. • Recomended over femoral cannulation as prophylaxis against malperfusion, lower extrmity ischemia,retrograde dissection and retrograde embolization of debris • Time consuming. • Impossible to CNS perfusion if dissected. • Brachial plexus injury. • Vascular complication. Axillary artery cannulation in type A aortic dissection operations. J Thorac Cardiovasc Surg 1999 Axillary cannulation in acute ascending aortic dissections Ann Thorac Surg 2000

47. Left Common Carotid Artery Cannulation for Type A Aortic Dissections • For cases that neither right axillary artery nor femoral artery can be used • Abdominal aortic stenosis/ dissection both axillary arteries Tex Heart Inst J. 2003; 30(2): 128–129

48. Useful in all patients with acute type A dissection. • A major advantage is quicker than others conventional methods as no purse-strings or additional dissection is required.

50. Surgical options for repair • Supracommissural ascending aorta replacement.(ascending aortic replacement) • Composite conduit root replacement. • Aortic valve-sparing root replacement. • ± Hemiarch Replacement • ± Total Arch Replacement • ±Hybrid-Procedures ( Frozen-elephant trunk)