Interfacility Transfer of Medicare Beneficiaries With Acute Type A Aortic Dissection and Regionalization of Care in the United States

When to Consider Deferral of Surgery in Acute Type A Aortic Dissection: A Review

Background

Acute type A aortic dissection (ATAAD) is a surgical emergency with an operative mortality of up to 30%, a rate which has not changed meaningfully in over two decades. A growing body of research has highlighted several comorbidities and presenting factors in which delay or permanent deferral of surgery may be considered; however, modern comprehensive summative reviews are lacking. The urgency and timing of this review are underscored by significant challenges in resource utilization posed by the COVID-19 pandemic. This review provides an update on the current understanding of risk assessment, surgical candidacy, and operative timing in patients with ATAAD.

Methods

A literature search was conducted through PubMed and Embase databases to identify relevant studies relating to risk assessment in ATAAD. Articles were selected via group consensus based on quality and relevance.

Results

Several patient factors have been identified which increase risk in ATAAD repair. In particular, frailty, advanced age, prior cardiac surgery, and use of novel anticoagulant medications have been studied. The understanding of malperfusion syndromes has also expanded significantly, including recommendations for surgical delay. Finally, approaches to triage have been significantly influenced by resource limitations related to the ongoing COVID-19 pandemic. While medical management remains a reasonable option in carefully selected patients at prohibitive risk for open surgery, endovascular therapies for treatment of ATAAD are rapidly evolving.

Conclusions

Early surgical repair remains the preferred treatment for most patients with ATAAD, however, improvements in risk stratification should guide appropriate delay or permanent deferral of surgery in select individuals.

Type A aortic dissection in the East and West: A comparative study between two hospitals from China and the US

BACKGROUND

In this study, we compare the clinical characteristics, intraoperative management, and postoperative outcomes of patients with acute type A aortic dissection (ATAAD) between two academic medical hospitals in the United States and China.

METHODS

From January 2011 to December 2017, 641 and 150 patients from Nanjing Drum Tower Hospital (NDTH) and Massachusetts General Hospital (MGH) were enrolled. Patient demographics, clinical features, surgical techniques, and postoperative outcomes were compared.

RESULTS

The annual number of patients presenting with ATAAD at MGH remained relatively stable, while the number at NDTH increased significantly over the study period. The average age was 51 years at NDTH and 61 years at MGH (P < .001). The percentage of patients with known hypertension at the two centers was similar. The time interval from onset of symptoms to diagnosis was significantly longer at NDTH than MGH (11 vs 3.5 hours; P < .001). Associated complications at presentation were more common at NDTH than MGH. More than 90% of patients (91% NDTH and 92% MGH) underwent surgery. The postoperative stroke rate was higher at MGH (12% vs 4%; P < .001); however, the 30-day mortality rate was lower (7% vs 16%; P = .006).

CONCLUSIONS

There was a significant increase in the number of ATAAD at NDTH during the study period while the number at MGH remained stable. Hypertension was a common major risk factor; however, the onset of ATAAD at NDTH was nearly one decade earlier than MGH. Chinese patients tended to have more complicated preoperative pathophysiology at presentation and underwent more extensive surgical repair.

Management of Acute Aortic Dissection During Critical Care Air Medical Transport

Acute aortic dissection is a time-critical emergency that air medical teams must be capable of transporting. Aortic dissections can manifest a myriad of complications in which prompt recognition and tailored treatments may mitigate additional physiological burden and limit dissection flap propagation. The purpose of this review is to discuss specific critical scenarios that air medical providers may be faced with and to equip them with a pathophysiological understanding of the disease and best practices for the management of acute aortic dissections.

Transesophageal Echocardiography, Mortality, and Length of Hospitalization after Cardiac Valve Surgery

BACKGROUND

Despite recommendations regarding the use of intraoperative transesophageal echocardiography (TEE), there is no randomized evidence to support its use in cardiac valve surgery. The purpose of this study was to compare the clinical outcomes of patients undergoing open cardiac valve repair or replacement surgery with and without transesophageal echocardiographic monitoring. The hypothesis was that transesophageal echocardiographic monitoring would be associated with lower 30-day mortality and shorter length of hospitalization.

METHODS

In this observational retrospective cohort study, Medicare claims were used to test the association between perioperative TEE and 30-day all-cause mortality and length of hospitalization among patients undergoing open cardiac valve repair or replacement surgery between January 1, 2010, and October 1, 2015. Baseline characteristics were defined by inpatient and outpatient claims. Medicare death records were used to ascertain 30-day mortality. Statistical analyses included regression models and propensity score matching.

RESULTS

A total of 219,238 patients underwent open cardiac valve surgery, of whom 85% underwent TEE. Patients who underwent TEE were significantly older and had greater comorbidities. After adjusting for patient demographics, clinical comorbidities, surgical characteristics, and hospital factors, including annual surgical volume, the TEE group had a lower adjusted odds of 30-day mortality (odds ratio, 0.77; 95% CI, 0.73 to 0.82; P < .001), with no difference in length of hospitalization (<0.01%; 95% CI, -0.61% to 0.62%; P = .99). Results were similar across all analyses, including a propensity score-matched cohort.

CONCLUSIONS

Transesophageal echocardiographic monitoring in cardiac valve repair or replacement surgery was associated with lower 30-day risk-adjusted mortality, without a significant increase in length of hospitalization. These findings support the use of TEE as routine practice in open cardiac valve repair or replacement surgery.

Distal Extent of Surgery for Acute Type A Aortic Dissection

Acute type A aortic dissection (TAAD) is a complex disease associated with extremely high morbidity and mortality for which we advocate a coordinated, protocol-driven system of care delivery that begins at patient diagnosis and continues throughout and beyond aortic reconstruction. Essential components of TAAD repair include prompt restoration of true lumen blood flow with obliteration of the false lumen flow, resection of the primary tear sites, restoration of valvular competency, and elimination of any organ malperfusion. This article focuses specifically on extent of repair of the aortic arch and explains our protocols regarding cannulation location and technique, cerebral and distal organ protection strategy, management of the brachiocephalic vessels, and extent of distal aortic reconstruction. We describe an operative strategy for TAAD repair that includes (1) continuous neurocerebral monitoring in all cases, (2) uninterrupted antegrade and/or retrograde cerebral perfusion (depending upon extent of arch repair) during open arch reconstruction, (3) aortic arch replacement technique with or without brachiocephalic vessel replacement using a custom trifurcate graft, and (4) descending aortic stabilization with or without the use of an elephant or frozen elephant trunk (distal stent graft). Our protocol for extent of aortic arch and brachiocephalic reconstruction has been standardized and is predicated on distinct pathoanatomic findings and/or cerebral malperfusion that are outlined.