Cannulation of the left common carotid artery for proximal aortic repair

Mild-to-moderate hypothermia in aortic arch surgery using circulatory arrest: a change of paradigm?

OBJECTIVES

Antegrade cerebral perfusion makes deep hypothermia non-essential for neuroprotection; therefore, there is a growing tendency to increase the body temperature during circulatory arrest with selective brain perfusion. However, very little is known about the clinical efficacy of mild-to-moderate hypothermia for ischemic organ protection during circulatory arrest. The aim of this study was to evaluate the safety and efficiency of mild-to-moderate hypothermia for lower-body protection during aortic arch surgery with circulatory arrest and antegrade cerebral perfusion.

METHODS

Between January 2005 and December 2009, a total of 347 patients underwent non-emergent arch surgery. In all patients, the systematic cooling was adapted to the expected time of circulatory arrest, and cerebral perfusion was performed at a constant blood temperature of 28 °C. There were 40 cardiac or aortic re-operations, 312 patients had concomitant aortic valve or root surgery, and 10 patients had replacement of the descending aorta. All examined data were collected prospectively.

RESULTS

The duration of circulatory arrest and the deepest rectal temperature were 18±11 min (range, 6-70 min) and 31.5±1.6 °C (range, 26.0-35.0 °C) for all 347 patients, and 34±12 min (range, 17-70 min) and 29.9±1.7 °C (range, 26.0-34.6 °C) for 77 patients having total/subtotal arch replacement. The maximum serum lactate level on the first postoperative day was, on average, 2.3±1.2 mmol l(-1). In the statistical analysis, no association between the duration of temperature-adapted circulatory arrest and lactate, creatinine, or lactate dehydrogenase levels after surgery could be demonstrated. The 30-day mortality was 0.9%. Permanent neurological deficit or temporary dysfunction occurred in three (0.9%) and eight (2.3%) patients, respectively. No paraplegia and no hepatic failure were reported; however, mesenteric ischemia occurred in one patient with severe stenosis of the celiac and upper mesenteric arteries. Temporary dialysis was necessary primarily after surgery in five patients. All of them underwent hemiarch replacement only, and four patients had an increased creatinine level before surgery.

CONCLUSION

Systemic mild-to-moderate hypothermia that is adapted to the duration of circulatory arrest is a simple, safe, and effective method of organ protection and can be recommended in routine aortic arch surgery with circulatory arrest and cerebral perfusion.

What is the best method for brain protection in surgery of the aortic arch? Selective antegrade cerebral perfusion

Despite considerable progress in the operative management of lesions involving the transverse aortic arch, replacement of this portion of the vessel remains a surgical challenge and is still associated with mortality and morbidity. This situation is due not only to the technical difficulties of the procedure but, often, to the unsatisfactory preservation of the integrity of the central nervous system during the period of arch exclusion. The techniques of cerebral protection during surgery of the aortic arch can be divided into those aimed at suppressing the metabolic demand of the central nervous system and those aimed at maintaining the metabolic supply during the time of exclusion of the cerebral vessels. Whichever technique is used, it must maintain the normal metabolism of the central nervous system or, at least, allow restoration of the physiologic conditions of its function. In this regard, selective antegrade cerebral perfusion has demonstrated experimentally and clinically its superiority over the other proposed protective techniques.

Carotid artery cannulation in aortic surgery

OBJECTIVE

Carotid artery cannulation was initially established at our clinic for surgery of acute aortic dissection, and it became the standard approach for procedures in which circulatory arrest is necessary. The aim of the study was to evaluate this method's efficiency regarding postoperative outcomes after the first 100 procedures.

METHODS

Between July 2002 and October 2005, 100 patients underwent aortic surgery using carotid artery cannulation by a side graft for arterial return with a mean flow rate of 4.6 +/- 0.5 L/min. There were 27 patients with acute and 2 with chronic type A aortic dissection. Sixteen patients had had prior cardiac surgery. During circulatory arrest, the arterial line was used for unilateral cerebral perfusion in moderate hypothermia (mean rectal temperature 28 degrees C +/- 1.6 degrees C) with a mean flow rate of 0.85 +/- 0.2 L/min.

RESULTS

Carotid artery cannulation offered adequate arterial return in all patients. In no case was a switch to another cannulation site necessary for arterial return. Furthermore, no complications related to the cannulation site were observed. One patient with acute dissection and 1 with chronic aneurysm died during the early postoperative course. Thus, 30-day mortality was 2.0% for the whole group and 3.7% for the dissection group. Two patients with severe calcification of the aortic valve had strokes. There were no strokes in the dissection group, although there were preoperative signs of cerebral malperfusion in 4 patients.

CONCLUSIONS

Carotid artery cannulation is a fast, safe, and efficient method of arterial cannulation even in very obese patients. In addition, it simplifies the procedure of unilateral cerebral perfusion through the arterial line during circulatory arrest, making it completely unnecessary to interrupt cerebral perfusion.

Valve-Sparing Aortic Root Repair With Patch Technique

BACKGROUND

In the valve-sparing aortic root repair technique presented, each pathologic sinus is replaced with a teardrop-shaped patch. In this study, the clinical and echocardiographic results after the first 20 procedures are evaluated.

METHODS

Between September 2000 and May 2004, 20 patients underwent aortic root repair using a patch technique. Eight patients had an acute type A aortic dissection and 12 patients had an aneurysm of the ascending aorta. In 12 cases, the aortic root was reconstructed with three patches, in 1 case with two patches, and in 7 cases with one patch.

RESULTS

The postoperative echocardiography at discharge showed no aortic regurgitation in 15 cases and trivial regurgitation in 5 cases. Three patients with aortic dissection as an initial pathologic diagnosis died during a median follow-up period of 14.5 months (range, 0.5 to 32 months). At the time of follow-up, the echocardiographic findings in all 17 survivors remained unchanged from the early postoperative examinations. Median peak and mean transvalvular gradients were 8 mm Hg (range, 3.2 to 14 mm Hg) and 4 mm Hg (range, 1.7 to 6 mm Hg), respectively.

CONCLUSIONS

The technique presented allows an individualized reconstruction of the sinuses of Valsalva, a simplified sizing of the vascular graft, and the creation of a new sinotubular junction resulting in good hemodynamic conditions. The technique is especially advantageous in patients in whom replacement of all sinuses is not necessary.

Femoral Versus Aortic Cannulation for Surgery of Chronic Ascending Aortic Aneurysm

BACKGROUND

Femoral artery cannulation and retrograde arterial perfusion have been postulated to increase the risk of cerebral embolism. In this study, the impact of the arterial cannulation site on the perioperative results after proximal aortic surgery is evaluated.

METHODS

Between January 1996 and December 2002, a total of 327 patients underwent proximal aortic repair for chronic non-dissected aortic disease. The arterial inflow was established by cannulation of the aortic arch (group A) or the femoral artery (group F) in 166 and 161 patients, respectively.

RESULTS

The early 30-day mortality was 0.9% (3 patients [1 patient in group A and 2 patients in group F]). The overall rate of early focal neurologic dysfunction (permanent and transient) was 4% (13 patients) and there was no significant difference between the two groups (4.2% vs 3.7%). Due to an intraoperative injury of the arterial wall, there were 6 repairs (3.6%) of the aortic arch in group A and 1 repair (0.6%) of the femoral artery in group F. The univariable examination of preoperative and intraoperative variables demonstrated that hypertension and increased cholesterol level could be possible independent risk factors for neurologic morbidity. In the following stepwise logistic regression, only the preoperative hypercholesterolemia was identified as an independent predictor for postoperative focal neurologic dysfunction.

CONCLUSIONS

The arterial inflow via the femoral artery and the subsequent retrograde perfusion during cardiopulmonary bypass do not increase the risk of neurologic complications in patients who undergo proximal aortic repair due to chronic non-dissected aortic aneurysm. Because there is an increased risk of aortic wall injury during cannulation, the femoral artery seems to be more suitable in these cases for cannulation than the proximal aorta.

Atresia of the Right Vertebral Artery in a Patient with Acute Aortic Dissection

A 49-year-old man had severe neurocognitive dysfunction after urgent operation for acute type A aortic dissection. Complete aortic arch replacement with single reimplantation of the arch branches was performed with the patient under deep hypothermic circulatory arrest. Retrospectively, my colleagues and I consider the atresia of the right vertebral artery to be responsible for this complication and discuss whether knowledge of the anomaly and adapting the operative strategy accordingly would have improved the neurologic outcome.