Efficacy of unilateral cerebral perfusion for brain protection in aortic arch surgery.

OBJECTIVES: The aim of the study was to evaluate the surgical and neurological outcomes after aortic arch surgery using unilateral cerebral perfusion. METHODS: Between June 2004 and February 2017, a total of 1000 patients (mean age 63 ± 12; range, 14-88 years) with nonacutely dissected aortic pathology (aneurysm, porcelain aorta, chronic dissection, infection, and injury in 89.1%, 4.9%, 4.1%, 1.6%, and 0.3%, respectively) underwent aortic arch surgery using unilateral cerebral perfusion for brain protection using mild hypothermia. A previous neurological event with residuals was documented in 3.6% of the patients and 12.2% had received previous cardiovascular surgery. The surgery comprised total/subtotal arch repair (with involvement of at least 1 supra-aortic artery) or hemiarch replacement in 346 and 654 patients, respectively. The aortic valve was replaced in 521 (including 190 valve composite grafts) and repaired in 380 patients (284 valve-sparing root repairs). RESULTS: The unilateral cerebral perfusion (mean duration 23.3 ± 17.2; range, 6-105 minutes) was performed via cannulated common carotid or innominate artery and aimed for a pressure-controlled (70-100 mm Hg) flow (mean flow, 1.4 ± 0.3 L/min; mean pressure, 90.1 ± 20.1 mm Hg) at a constant blood temperature of 28°C for ensuring the patency of collateral pathways. The circulatory arrest of the lower body (mean duration 18.4 ± 9.9 minutes) was performed at a rectal temperature of 31.2 ± 1.8°C. Early (30-day) and in-hospital mortality was 1.3% and 2.1%, respectively; the rates of permanent neurological deficit and transient neurological dysfunctions were 1.0% and 4.9%, respectively. CONCLUSIONS: Unilateral cerebral perfusion performed in the described conditions is highly effective for cerebral protection in aortic arch surgery.

Operative and Long-Term Outcomes After Curative Repair of Acute Dissection Involving the Proximal Aorta.

BACKGROUND: The aim of the study was to evaluate operative and long-term results after acute type A aorta dissection (AAAD) operation, in which complete resection of all dissected aortic segments (curative repair) was achieved. METHODS: Among 205 consecutive patients operated on between 2002 and 2014 because of AAAD were 88 patients (42.9%), in whom the dissection did not extend into the downstream aorta. The distal extension of the dissection ended before the origin of the innominate artery in 50 patients of the study cohort (56.8%) or extended throughout the arch, necessitating a total/subtotal arch replacement to achieve a curative distal repair in 38 remaining patients (43.2%). The aortic root was involved in 52 patients (59.1%) and was repaired using valve-sparing repair (31) or replacement with a valve composite graft (21). Combination of root and open arch surgery was reported in 46 patients (52.3%). RESULTS: Thirty-day and in-hospital mortalities were 3.4% and 5.7%, respectively. Survival was estimated starting with the operation and was 81.9% ± 4.5% and 56.6% ± 8.7% at 5 and 10 years, respectively. No patient required reoperation on the aortic root and/or distal thoracoabdominal aorta; however 2 cardiac reoperations were unrelated to the primary surgical procedure. Moreover, the freedom of aortic and/or sudden/unknown death was 100%. CONCLUSIONS: Curative aortic repair can be achieved in a relevant share of AAAD patients and is mostly limited by the distal extension of dissection. This kind of repair is advisable, whenever possible, because it can provide very low risk of aortic complications and/or reoperations over time.

Innominate artery pathology in the setting of aortic arch surgery: incidences, surgical considerations and operative outcomes.

OBJECTIVES: The aim of the study was to evaluate the incidences of innominate artery (IA) involvement in aortic arch pathology necessitating surgery, the surgical strategies and the operative results. METHODS: Among the 366 patients who underwent total/subtotal arch replacement because of non-acutely dissected aortic pathology between 2004 and June 2017, there were 46 (12.6%) patients (29 males; mean age 69 ± 10, range 35-84 years) with IA involvement. Pathologies necessitating replacement of the IA were chronic aneurysm including progression of chronic dissection, severe atherosclerosis with or without an aneurysmatic dilatation, and inflammatory vasculitis in 34, 11 and 1 patient, respectively. All data were collected prospectively, and intention-to-treat analysis was performed. RESULTS: All patients underwent total/subtotal aortic arch replacement using unilateral cerebral perfusion (mean duration 44.6 ± 15.7 min) under mild hypothermia (30.6 ± .4°C). In addition to arch and IA replacement, repair of one or two further supra-aortic arteries was performed in 20 and 23 patients, respectively. One patient underwent complete thoracic aorta replacement via clamshell thoracotomy. The aortic valve, which was the most frequent object of concomitant surgery, was replaced in 18 (including 3 valve composite-grafts) and repaired in 20 (18 valve-sparing root repairs) patients. Early (30-day and/or in-hospital) mortality was 0. The rate of permanent neurological deficit was 2.2% (1 patient with a huge, partially thrombosed arch and innominate aneurysm). Transient neurological dysfunctions such as agitation were observed in 6 patients. CONCLUSIONS: Involvement of the IA in aortic arch surgery is not infrequent, and its concomitant replacement using well-considered cannulation, perfusion and surgical strategy offers excellent operative outcomes.

Acute aortic dissection involving the root: operative and long-term outcome after curative proximal repair.

OBJECTIVES: The aim of the study was to evaluate operative and long-term results after surgery of acute aortic dissection involving the root, in which the proximal repair consisted of curative resection of all dissected aortic sinuses and was performed using either valve-sparing root repair or complete root replacement with a valve conduit. METHODS: Between August 2002 and March 2013, 162 consecutive patients (mean age 63 ± 14 years) underwent surgery for acute type A aortic dissection. Eighty-six patients with an involvement of the aortic root underwent curative surgery of the proximal aorta consisting of valve-sparing root repair (n = 54, 62.8%) or complete valve and root replacement using composite valve grafts (n = 32, 37.2%). In patients with root repair, all dissected aortic walls were resected and root remodelling using the single patch technique (n = 53) or root repair with valve reimplantation (n = 1) was performed without the use of any glue. All perioperative data were collected prospectively and retrospective statistical examination was performed using univariate and multivariate analyses. RESULTS: The mean follow-up was 5.2 ± 3.5 years for all patients (range 0-12 years) and 6.1 ± 3.3 years for survivors. The 30-day mortality rate was 5.8% (5 patients), being considerably lower in the repair sub-cohort (1.9 vs 12.5%). The estimated survival rate at 5 and 10 years was 80.0 ± 4.5 and 69.1 ± 6.7%, respectively. No patient required reoperation on the proximal aorta and/or aortic valve during the follow-up time and there were only two valve-related events (both embolic, one in each group). Among those patients with repaired valves, the last echocardiography available showed no insufficiency in 40 and an irrelevant insufficiency (1+) in 14. CONCLUSIONS: Curative repair of the proximal aorta in acute dissection involving the root provides favourable operative and long-term outcome with very low risk of aortic complications and/or reoperations, regardless if a valve-sparing procedure or replacement with a valve conduit is used. Valve-sparing surgery is frequently suitable, providing excellent outcome and very high durability.

Open aortic arch surgery in chronic dissection with visceral arteries originating from different lumens.

OBJECTIVES: Surgical management of chronic aortic dissection is controversial, especially when the dissection extends into the abdominal aorta in which the visceral arteries originate from different lumens and is combined with aortic arch pathology necessitating surgery. The aim of the study was to evaluate the results of open surgery in this complex aortic pathology. METHODS: Between June 2002 and 2015, a total of 17 patients (median age 57, range 32-76 years) necessitating complete arch replacement presented complex chronic dissection of the thoraco-abdominal aorta with the visceral arteries originating from different lumens. Fourteen patients (82%) had had previous cardiac surgery, which was performed on the proximal aorta in all but one because of acute type A dissection. Nine patients without considerable dilatation of the descending aorta received aortic arch replacement with distal resection of the dissection membrane, and 8 patients with progressive dilatation of the thoracic aorta underwent aortic arch and descending aorta replacement via clamshell approach. RESULTS: No early (defined as 30-day, 90-day and in-hospital period) deaths, strokes or spinal cord injuries occurred. Only 1 patient (6%) presented temporary neurological dysfunctions (delirium, agitation), which resolved completely before discharge, and an injury of the recurrent laryngeal nerve was documented in 2 patients (12%). Temporary dialysis was necessary in 1 case. The follow-up was complete for all patients. All but one patient, who died due to leukaemia 23 months after surgery, were alive at the last follow-up (median duration 33 months, range 2-118 months). No patient needed a reoperation or an intervention on the thoracic and/or abdominal aorta. Moreover, no noticeable progression of the chronic dissection in the downstream aorta was documented in any patient. CONCLUSIONS: The results after conventional aortic arch repair with distal resection of the dissection membrane and, if necessary, with replacement of the progressively dilated chronic dissected thoracic aorta can offer excellent results in experienced hands and, therefore, this technique may be considered as a preferable option for surgical treatment of chronic aortic dissection with involvement of the aortic arch and the visceral arteries originating from different lumens.

Impact of surgical experience on outcome in surgery of acute type A aortic dissection.

OBJECTIVES: The study was conducted to evaluate our results of acute aortic dissection repair taking into account the impact of surgical experience in aortic surgery. METHODS: Between August 2002 and March 2013, 162 consecutive patients (mean age: 63 ± 14 years) underwent surgery for acute type A aortic dissection. All patients were operated on by one of the clinic's attending surgeons with wide experience in cardiac surgery (at least 2000 procedures performed personally), however about one-half of the patients (75 patients, 46%) were operated by the aortic team (AT) surgeons with profound experience in complex aortic pathologies. All perioperative data were collected prospectively and retrospective statistical analysis was performed using uni- and multivariate analyses to identify predictors for surgical adverse outcome (AO) containing in-hospital and/or 90-day mortality and new permanent neurological and organ dysfunctions. RESULTS: AO was observed in 36 patients (22.2%) including in-hospital mortality in 22 (13.6%). Multivariate logistic regression analysis identified surgery not performed by the AT as the strongest predictor for AO (odds ratio: 14.1; 95% confidence interval: 3.5-55.6; P < 0.0001) followed by any malperfusion, myocardial infarction and creatinine level. Two groups were built according to the surgery performed by the AT (Group AT) or by the surgeons not on the AT (Group No-AT). The comparison of the groups showed no relevant differences regarding the preoperative characteristics, especially compromised consciousness, malperfusion and extent of dissection. Yet, the outcomes in Group AT vs No-AT were significantly different presenting AO: 8.0 vs 34.5% (P < 0.0001), in-hospital mortality: 4.0 vs and 21.8% (P < 0.001), new permanent neurological deficit: 2.7 vs 11.5% (P = 0.03), even if valve-sparing repairs and complete arch replacements were much more frequent in Group AT. The groups also differed considerably in regard to cannulation and perfusion management, which might play a decisive role in surgical outcome. CONCLUSIONS: Aortic repair in acute type A dissection, when performed by highly specialized aortic surgeons, offers not only much better outcomes but also provides significantly higher rate of curative albeit valve-sparing aortic repairs. Patient-centred care in referral aortic centres with surgery performed by specialized teams should be striven for to improve surgical results in acute aortic dissection surgery.

Presentation of a quality management program in off-pump coronary bypass surgery.

OBJECTIVE: To increase the number of off-pump coronary procedures at our institution, a new surgical team was formed. The first 3 years of "learning period" were accompanied by a quality management program aimed to control and adjust the surgical process and to ensure the safety and quality of the procedure. METHODS: All patients were operated on by the same surgeon between January 2004 and December 2006; all procedures were performed under the following quality management protocol. First, a flow chart regulated surgical and anesthetic details. Second, an online file, named "disturbance file," was used to report work flow interruption, disturbance, and intraoperative events, that is, myocardial ischemia, hypotension, conversion to cardiopulmonary bypass, and any violation of the protocol. Each event was coded with 1 point and added to a score (the higher the score is, the greater the disturbance). Outcome parameters known as major events-major cardiac and cerebral events: mortality within 30 days/myocardial infarction confirmed by electrocardiogram or significantly high levels of total creatine kinase-myocardial muscle creatine kinase/reintervention within 30 days/stroke--and new-onset dialysis were also measured. Success was defined as freedom from any of those events and depicted in a cumulative sum control (CUSUM) chart. Outcome data and CUSUM were correlated with the intraoperative Disturbance Index. RESULTS: In total, 490 off-pump coronary bypass operations were performed by the named surgeon during the study period. The 30-day mortality was reduced from 4.0% to 1.9%. Disturbance Index score of greater than 1 declined from 41.6% to 23.3%. All major cardiac and cerebral events declined. The CUSUM chart showed two critical periods during the learning period, which made an adjustment of the protocol necessary. CONCLUSIONS: Quality management control is efficient in improving the postoperative results of a surgical procedure. A learning period is of cardinal importance for any new team wishing to engage in a novel surgical technique.

Open aortic arch replacement in the era of endovascular techniques.

OBJECTIVES: Despite the progress in protection and surgical techniques, the proponents of endovascular techniques for aortic arch repair still consider conventional arch replacement to be high risk, mostly due to deep hypothermia, which in the past was generally used for cerebral and organ protection. The aim of the study was to evaluate the operative results of open aortic arch replacement using current perfusion and surgical techniques in which deep hypothermia is avoided. METHODS: Between October 2004 and February 2012, 131 consecutive patients with non-acute-dissected aortic arch pathology (mean age: 66 ± 11 years) were referred for surgery. All patients were operated on conventionally using circular aortic arch replacement with repair of one (10), two (58) or all arch branches (63). The adjacent aorta was replaced in all cases (ascending--115, descending--2 and both--14). Nine (6.9%) patients had previous neurological defects with residual symptoms and 17 (13.0%) had previous cardiac surgery. RESULTS: Either unilateral (130) or bilateral (1) cerebral perfusion at a blood temperature of 28°C (mean duration 36 ± 14, range: 16-80 min) was performed for brain protection during circulatory arrest under mild-to-moderate hypothermia (mean rectal temperature 30.0 ± 1.6°C). Concomitant cardiac procedures, mostly on the aortic valve, were necessary in 121 (92%) patients. Among 114 patients needing aortic valve/root surgery, there were 70 aortic valve-preserving procedures. Permanent neurological deficit or temporary dysfunctions occurred in 1 (0.8%) and 6 patients (4.6%), respectively. No patient suffered from paraplegia. The postoperative 30-day mortality was 2.3% (3 patients). A total of 17 patients died during the follow-up time of up to 97 months (mean 37 ± 27 months), resulting in an actuarial survival of 81.9 ± 4.3% at 5 years. No patient needed any reoperation or new intervention on the repaired aorta. CONCLUSIONS: Conventional arch surgery offers definitive repair and can be safely performed using current perfusion and operative techniques. Open procedures ensure simultaneous aortic valve repair, which is frequently necessary, and can be performed by reconstruction in more than half of the cases. The use of refined surgical and cerebral perfusion techniques allows the avoidance of deep hypothermia with all its negative side effects and leads to excellent outcomes against which the results of alternative approaches should be compared.

Near-infrared spectroscopy for neuromonitoring of unilateral cerebral perfusion.

OBJECTIVES: There is neither consensus regarding which methods of neuromonitoring are adequate and reliable for assessing cerebral cross-perfusion during unilateral cerebral perfusion (UCP) nor are any threshold values defined. The aim of the study was to evaluate the usefulness of near-infrared spectroscopy (NIRS) for the neuromonitoring of right-sided UCP, which is increasingly used for cerebral protection as a consequence of the recent rise in supra-aortic cannulation methods. METHODS: For the purpose of the study, 122 patients (mean age 67 ± 12 years) who underwent open aortic arch surgery between August 2007 and July 2011 using right-sided UCP with a duration time exceeding 20 min were evaluated. The neuromonitoring consisted of NIRS and pressure measurement in both radial arteries in all patients. Forty-four (36%) patients suffered acute aortic dissection (3 having cerebral malperfusion), and 89 (73%) underwent total or subtotal arch replacement. Logistic regression analysis was used to model neurological adverse outcome (permanent and temporary neurological dysfunctions) as a function of cerebral oxygen saturation and other covariates. RESULTS: During UCP (mean duration 38 ± 18 min) performed at a constant blood temperature of 28°C, the mean brain oxygen saturation dropped on the non-direct perfused side from 66 to 61% on average, corresponding to 92% of the baseline. In only 1 patient, an insufficient cross-over perfusion was presumed due to an intense drop of the saturation to 15% and was treated by employment of bilateral perfusion. In all remaining patients, the drop was not below 40% and/or 70% of the baseline. In the adjusted analysis, acute aortic dissection could be found as an independent predictor of an adverse neurological outcome (5 permanent, all in acute dissections, and 9 temporary dysfunctions), while there was no association between the occurrence of adverse neurological outcome and the values of regional cerebral oxygen saturation during UCP. CONCLUSIONS: NIRS seems to be a reliable instrument to recognize a relevant disruption of cerebral cross-perfusion during UCP. A drop of brain oxygen saturation to 40% and/or 70% of the baseline can be considered a threshold value for sufficient cerebral cross-perfusion, at least under the flow and temperature management presented.

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.