Epiaortic ultrasound assessment of the aorta in cardiac surgery

Mortality Reduction After a Preincision Safety Check Before Cardiac Surgery: Is It the Aorta?

OBJECTIVES

The introduction and use of a preincision safety check were associated with lower mortality after mixed adult cardiac surgery; however, an explanatory mechanism is lacking. Stroke, one of the most severe complications after cardiac surgery, with high mortality, may be reduced by adapting the surgical handling of the ascending aorta. This study assessed the prevalence and predictors of this adaptation after a preincision safety check and the subsequent effect on outcome.

DESIGN

A prospective, single-center, observational study comparing adaptation with no-adaptation. The primary outcome measure was 30-day mortality. Multivariate analyses were performed to determine independent predictors of adaptation. To study the effect of adaptation on outcome, a propensity score-matched cohort was constructed in a 1:3 intervention:control ratio.

SETTING

At Isala Zwolle (NL), a large, nonacademic teaching hospital.

PARTICIPANTS

All consecutive cardiac surgery procedures from 2012 until 2015, including 4,752 surgeries.

INTERVENTIONS

The adaptation of surgical handling of the ascending aorta.

MEASUREMENTS AND MAIN RESULTS

In 283 cardiac surgeries (5.9%), adaptation was indicated. The most important independent predictors for adaptation were extracardiac atherosclerosis, current smoking, and increasing age. In the propensity score-matched cohort consisting of 1,069 procedures, there were no significant differences in outcome. After correction for propensity score, the hazard ratio of adaptation for 30-day mortality was 1.8 (0.85-3.79).

CONCLUSIONS

The adaptation of aortic surgical handling after a preincision safety check was necessary for 5.9% of cardiac surgeries, with extracardiac atherosclerosis as the strongest predictor. Outcome was not significantly different between patients with and without adaptation. Although promising, it remains unclear whether adaptation may fully explain mortality reduction after the use of a preincision safety check.

The Epiaortic Ultrasound Diagnosis of Iatrogenic Subadventitial Hematoma

Iatrogenic aortic injury is a rare but potentially lethal complication of cardiac surgery. While sometimes resulting in aortic dissection or intramural hematoma, injury more frequently results in subadventitial hematoma, a more benign pathology. Here, we describe a case where intraoperative transesophageal echocardiography (TEE) identified such a hematoma but was unable to rule out dissection. Epiaortic ultrasound was subsequently performed, which definitively demonstrated the absence of a dissection flap or extraluminal flow. Per our review, this is the first report documenting the successful use of epiaortic imaging to identify subadventitial hematoma in the setting of inconclusive TEE findings.

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

BACKGROUND

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes.

METHODS

SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7 and 30 days.

RESULTS

Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P = .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P = .04).

CONCLUSIONS

Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

Tin-filtered low-dose chest CT to quantify macroscopic calcification burden of the thoracic aorta

OBJECTIVES

To compare a low-dose, tin-filtered, nonenhanced, high-pitch Sn100 kVp CT protocol (Sn100) with a standard protocol (STP) for the detection of calcifications in the ascending aorta in patients scheduled for cardiac surgery.

METHODS

Institutional Review Board approval for this retrospective study was waived and the study was HIPAA-compliant. The study included 192 patients (128 men; age 68.8 ± 9.9 years), of whom 87 received the STP and 105 the Sn100 protocol. Size-specific dose estimates (SSDE) and radiation doses were obtained using dose monitoring software. Two blinded readers evaluated image quality on a scale from 1 (low) to 5 (high) and the extent of calcifications of the ascending aorta on a scale from 0 (none) to 10 (high), subdivided into 12 anatomic segments.

RESULTS

The Sn100 protocol achieved a mean SSDE of only 0.5 ± 0.1 mGy and 0.20 ± 0.04 mSv compared with the mean SSDE of 5.4 ± 2.2 mGy achieved with the STP protocol (p < 0.0001). Calcification burden was associated with age (p < 0.0001), but was independent of protocol with mean calcification scores of 0.48 ± 1.23 (STP) and 0.55 ± 1.25 (Sn100, p = 0.18). Reader agreement was very good (STP κ = 0.87 ± 0.02, Sn100 κ = 0.88 ± 0.01). The STP protocol provided a higher subjective image quality than the Sn100 protocol: STP median 4, interquartile range 4-5, vs. SN100 3, 3-4; p < 0.0001) and a slightly better depiction of calcification (STP 5, 4-5, vs. Sn100 4, 4-5; p < 0.0001).

CONCLUSIONS

The optimized Sn100 protocol achieved a mean SSDE of only 0.5 ± 0.1 mGy while the depiction of calcifications remained good, and there was no systematic difference in calcification burden between the two protocols.

KEY POINTS

• Tin-filtered, low-dose CT can be used to assess aortic calcifications before cardiac surgery • An optimized Sn100 protocol achieved a mean SSDE of only 0.5 ± 0.1 mGy • The depiction of atherosclerosis of the thoracic aorta was similar with both protocols • The depiction of relevant thoracic pathologies before cardiac surgery was similar with both protocols.

Intraoperative Epiaortic Ultrasound for Traumatic Pseudoaneurysm of the Ascending Aorta

Epiaortic ultrasound is an imaging modality that is commonly used to evaluate the ascending aorta for atheroma and other mural lesions during elective cardiac surgery. Its use in contained aortic rupture has not been established. We present a case of thoracic trauma with contained pseudoaneurysm of the ascending aorta. At operation, the precise location of the aortic tear could not be identified by visual inspection, manual palpation, or transesophageal echocardiography. Epiaortic ultrasound was employed and the aortic defect was identified and successfully repaired. This intraoperative imaging modality may play an increasing role in the identification of aortic pathology when visual inspection and other intraoperative imaging is insufficient.

Imaging Techniques for Diagnosis of Thoracic Aortic Atherosclerosis

The most severe complications after cardiac surgery are neurological complications including stroke which is often caused by emboli merging from atherosclerosis in the ascending aorta to the brain. Information about the thoracic aorta is crucial in reducing the embolization risk for both surgical open and closed chest procedures such as transaortic heart valve implantation. Several techniques are available to screen the ascending aorta, for example, transesophageal echocardiography (TEE), epiaortic ultrasound, TEE A-view method, manual palpation, computed tomography, and magnetic resonance imaging. This paper provides a description of the advantages and disadvantages of these imaging techniques.

Ultra low-dose chest ct with iterative reconstructions as an alternative to conventional chest x-ray prior to heart surgery (CRICKET study): Rationale and design of a multicenter randomized trial

BACKGROUND

Stroke after cardiac surgery is a severe complication with a persistently high incidence of 1.4 - 9.7%. Postoperative strokes are mainly embolic and can be provoked by manipulation and clamping of the aorta during cardiac surgery, resulting in the mobilization of atherothrombotic material and calcifications from the aortic wall. Computed tomography (CT) can offer preoperative visualization of aortic calcifications with low radiation exposure. We hypothesize that preoperative knowledge regarding the location and extent of aortic calcifications can be used to optimize surgical strategy and decrease postoperative stroke rate.

METHODS/DESIGN

The CRICKET study (ultra low-dose chest CT with iterative reconstructions as an alternative to conventional chest x-ray prior to heart surgery) is a prospective multicenter randomized clinical trial to evaluate whether non-contrast chest CT before cardiac surgery can decrease postoperative stroke rate by optimizing surgical strategy. Patients scheduled to undergo cardiac surgery aged 18 years and older are eligible for inclusion. Exclusion criteria are pregnancy, a chest/cardiac CT in the past three months, emergency surgery, concomitant or prior participation in a study with ionizing radiation and unwillingness to be informed about incidental findings. Subjects (n = 1.724) are randomized between routine care, including a chest x-ray, or routine care with an additional low dose chest CT. The primary objective is to investigate whether the postoperative in-hospital stroke rate is reduced in the CT arm compared to the routine care arm of the randomized trial. The secondary outcome measures are altered surgical approach based on CT findings and cost-effectiveness.

Anesthetic Management for Cardiopulmonary Bypass

Cardiopulmonary bypass has revolutionized the practice of cardiac surgery and allows safe conduct of increasingly complex cardiac surgery. A brief review of the bypass circuit is undertaken in this review. A more thorough review of the anesthetic management is accomplished including choice of anesthetic medications and their effects. The inflammatory response to cardiopulmonary bypass is reviewed along with interventions that may help ameliorate the inflammation.

Novel emboli protection cannula during cardiac surgery: first animal study

Background

Stroke after open heart surgery is a major cause of morbidity and mortality. Up to 60% of intraoperative cerebral events are caused by emboli generated by manipulations of the aorta during surgery. This is the first animal study evaluating the safety and efficacy of a novel aortic cannula designed to extract solid and gaseous emboli during cardiac surgery.

Methods

Seven domestic pigs were connected to cardiopulmonary bypass using a CardioGard 24F aortic cannula. Three pigs that were cannulated with a standard aortic cannula were defined as controls. Several main flow and suction regimens were carried out. Osseous particles of different sizes were injected into the proximal aorta to simulate emboli.

Results

The CardioGard cannula demonstrated an overall emboli retrieval rate of 77%. A rate of 88.45% was demonstrated during the low-flow regimen used clinically during aortic manipulation. Gaseous and solid emboli were eliminated by suction, as demonstrated by epi-carotid ultrasound. No significant changes were observed in hemodynamic and laboratory parameters.

Conclusions

The CardioGard cannula is as simple to use as a regular commercially available aortic cannula, having a similar safety profile and proven efficacy in capturing intraoperative emboli.

Technological solutions for cardiac surgery in the elderly

The current review addresses contemporary technological advances in cardiac surgery performed on octogenarian patients, namely off-pump coronary artery bypass grafting (CABG), proximal anastomosis device, routine use of intraoperative epiaortic ultrasound, proximal anastomosis without clamping, transcatheter aortic valve implantation (TAVI), and brain protection during cardiac surgery.

Transesophageal echocardiography in noncardiac thoracic surgery

In high-risk surgeries with medically complicated patients, transesophageal echocardiography (TEE) adds an additional level of monitoring with which few can disagree. This article presents multiple applications of TEE that can assist both the anesthesiologist and the surgeon through major noncardiac thoracic surgery. It highlights how TEE can be used as an adjuvant to lung resection surgery; TEE as a monitor during lung transplantation; TEE to assess patients for extracorporeal membrane oxygenation; TEE for thoracic aortic surgery; and TEE in the assessment of patients with acute pulmonary hypertension undergoing noncardiac thoracic surgery.

Aortic atheroma and adverse cerebral outcome: risk, diagnosis, and management options

Aortic atheromatous disease is a common finding in the patient presenting for cardiac surgery. Adverse neurologic outcome has been closely linked to the extent of aortic atherosclerosis. In order to optimize perioperative outcomes, the location and severity of disease needs accurate characterization using multimodal techniques. Although various preoperative radiographic techniques have variably identified patients with significant atheroma, intraoperative echocardiographic imaging has proven most useful in localizing and characterizing the degree of aortic atheroma. Epiaortic assessment of the ascending aorta has been utilized in guiding surgical modifications and interventions aimed at reducing the risk of neurologic injury. Although no particular technique has been definitely studied, avoidance of the identifiable atheromatous aortic region has been a main feature of the various modifications employed to optimize neurologic outcome after cardiac surgery.