Funambulism by Anaesthetist: Intraoperative Management of Renal Transplantation in an Operated Case of Aortic Dissection

Respected Editor, Central aortic diseases in renal transplant recipients warrant staged or simultaneous aortic reconstruction to provide satisfactory long-term transplant durability.1 Even after successful reconstruction, progression of dissection and impending aortic rupture can occur depending on site, aortic diameter (>5.5cm), and hypertensive stress response.2,3 Thus, renal transplantation in the operated case of ascending aortic dissection with unrepaired descending aortic and carotid dissection is an anesthetic challenge, as it demands hemodynamic equilibrium within a narrow window. Moreover, vascular anastomosis in proximity to the dissected aorta in patients on anticoagulant demands meticulous dissection and surgical expertise. A 42-year-old female patient a known case of medically managed chronic kidney disease for 20 years; hypertensive for 10 years; underwent coiling for the right middle cerebral artery aneurysmal bleed before 8 years; operated for Stanford Type A aortic dissection before 2 years (Bentall's procedure + coronary artery bypass graft); requiring maintenance renal replacement therapy (three sessions/week through left arteriovenous fistula) for 2 years was posted for living donor renal transplant at our institute. The patient also underwent left subclavian vein angioplasty for pseudoaneurysm before 2 months. The donor was her 62-year-old father with well-controlled medically managed hypertension for 15 years. Her preoperative examination and blood investigations were in line with chronic kidney disease. Her transthoracic echo was suggestive of mild systolic dysfunction (ejection fraction – 40%) with the aortic valve gradient of 24 mmHg. The combined opinion of cardiovascular surgery (CTVS) and transplant surgery team was to proceed with right external iliac vessel transplant as aortic dissection was not progressing for the past 2 years, and iliofemoral Doppler was normal Figure 1. In view of the possibility of impending aortic rupture/dissection on the table and consequent risk of graft loss, limb loss, and on-table mortality, the patient was taken for renal transplantation after thoroughly discussing risk–benefit ratio with the patient and her relatives. Preoperatively, oral antihypertensives (nifedipine, clonidine, and carvedilol) and levetiracetam were continued as per schedule. Warfarin was stopped 5 days before surgery and switched to bridging unfractionated heparin 5000 IU 6 hourly till 6 h before surgery. The patient was taken for surgery with the CTVS team on standby and acceptable posthemodialysis reports. Baseline vitals were heart rate – 64/min, blood pressure – 110/64 mmHg, and Spo2 – 98% on room air with morning antihypertensives. Intraoperatively, balanced general anesthesia was given, and the airway was secured using a video laryngoscope. To achieve our hemodynamic goals (systolic blood pressure <130–140 mmHg; heart rate ~ 60–80/min), to ensure adequate perfusion of denervated renal graft and to identify de novo dissection, we used invasive cardiac output monitoring (Flotrac), bispectral index monitoring, and transesophageal echo. Goal-directed fluid therapy was given using 250 mL normal saline boluses to keep stroke volume variation (SVV) <15% and central venous pressure (CVP) – 12–14 mmHg Figure 2. Systemic vascular resistance (SVR) ~ 1000 dyn.s.m2/cm5 and cardiac output ~ 4 L/min/m2 were maintained with intravenous esmolol (50 µg/kg boluses), nitroglycerin (1–5 µg/kg/min), and fentanyl infusion (1 µg/kg/h). Immunosuppressants and diuretics were given as per routine institutional protocol. Transplant surgery proceeded after ensuring the normal condition of the recipient's vessels on the table. Vascular clamps were applied approximately 7 cm distal to the dissection site, and the left donor renal vessels were anastomosed with the right external iliac vessels of the recipient. The left laparoscopic donor nephrectomy was uneventful, with postnephrectomy urine output ~2 mL/kg/h. Intraoperative hemodynamics of the recipient remained stable with a turgid graft and immediate good urine output on the table after clamp release. The patient was extubated on the table pain free. Her postoperative course was smooth. On 1-year follow-up, the patient is doing well with good urine output, serum creatinine – 1.2 mg/dL, normal renal allograft Doppler study without any progression of aortic dissection.Figure 1: Pre transplant aortogram (Post Bentall surgery) showing unrepaired descending aortic and abdominal aortic dissection extending from celiac trunk upto right common iliac artery (as denoted by red arrow) inferiorly with apparently normal right external iliac artery distally. Superiorly it was extending upto origin of both common carotid arteries. LSA: Left subclavian artery, SMA: Superior mesenteric artery, LRA: Left renal artery, RRA: Right renal artery, RT CIA: Right common iliac arteryFigure 2: Intraoperative monitoringSVV (dynamic parameter)-guided fluid therapy and SVR-guided titration of blood pressure gave us liberty to expand the safety margin regarding conventional static target parameters such as MAP and CVP to achieve optimal graft function. We used a video laryngoscope with the head in a neutral position to prevent further carotid dissection.4 Chances of late rebleed in postcerebral aneurysm coiling cases are ~2%–9%. Maintenance of normocapnia, eunatremia, and avoidance of hypotensive episodes prevented it.5 Flotrac-guided fine balance of intraoperative hemodynamics and a vigilant anesthetic eye to quickly identify and manage de novo dissection is the key. Declaration of patient consent The patient consent has been taken for participation in the study and for publication of clinical details and images. Patients understand that the names and initials would not be published, and all standard protocols will be followed to conceal their identity. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.