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Introduction:
Patients with thoracic aortic pathology undergoing thoracic endovascular aortic repair (TEVAR) often have concomitant coronary arterial disease (CAD), which may cause perioperative myocardial infarction (MI), cardiac arrest, and/or death. Despite this risk, the need for and extent of preoperative cardiac work-up prior to TEVAR remains undefined. The present study seeks to assess the adequacy of a limited cardiac evaluation prior to TEVAR including assessment of cardiac symptomatology, resting electrocardiogram (ECG), and transthoracic echocardiography (TTE) as well as to estimate the incidence of perioperative cardiac events in patients undergoing TEVAR.
Methods:
Retrospective analysis of a prospectively maintained IRB-approved database was performed for all patients undergoing TEVAR at a single referral institution between 5/2002 and 6/2013. N=463 procedures involving TEVAR were identified. All procedures involving median sternotomy were excluded, and n=380 procedures (n=343 patients) were included in the final analysis. Degree of cardiac workup was classified based upon the most invasive procedure performed preoperatively. Classification was no workup, resting ECG only, resting TTE, exercise/pharmacologic stress testing, or coronary angiography. Standard workup consisted of assessment of cardiac symptomatology along with resting ECG and/or TTE, with further workup indicated for unstable symptoms, significantly abnormal ECG or TTE, or multiple cardiac risk factors. Categorical and continuous variables were compared using the chi-square test and analysis of variance (ANOVA), respectively.
Results:
Baseline characteristics are presented in table 1. N=28 (7.4%) patients had no pre-operative cardiac workup, n=127 (33.4%) had resting ECG only, n=208 (54.7%) had a resting echo, n=13 (3.4%) underwent stress testing, and n=4 (1.1%) had coronary angiography (only 1 required pre-operative percutaneous intervention) for cardiac workup. Patients undergoing stress testing or coronary angiography were older and had a higher incidence of known coronary artery disease (p<0.01) and prior MI (p=0.02). Significant differences were noted in procedural indications, procedure performed, patient ASA class, and procedure status (Tables 2 and 3). A total of n=9 (2.4%) patients experienced a peri-operative cardiac event (MI and/or cardiac arrest), with no significant difference noted amongst all groups (p=0.35), suggesting the extent of cardiac workup was appropriate. Incidence of 30-day/in-hospital and cardiac specific mortality was likewise similar amongst all groups (Table 3).
Conclusions:
Risk of a post-operative cardiac event following TEVAR is low (2.4%), and the data presented suggest that initial screening with either resting TTE or ECG, in addition to assessment of cardiac symptom status, is adequate in the vast majority of patients. As such, we recommend resting TTE and/or ECG as the initial cardiovascular screening mechanism in patients undergoing TEVAR, with subsequent more invasive studies if initial screening reveals cardiovascular abnormalities.

Table 1: Pre-Operative Characteristics

	All Patients (n=380)	No Workup (n=28)	ECG Only (n=127)	Echo (n=208)	Stress Test (n=13)	Coronary Angiography (n=4)	P-Value
Age (years)	64.3±14.7	47.5±16.5	63.6±14.8	66.7±13.1	66.4±10.3	73.8±11.5	<0.01
Male Sex	232 (61.1%)	15 (53.6%)	89 (70.1%)	118 (56.7%)	7 (53.9%)	3 (75.0%)	0.12
Hypertension	329 (86.6%)	14 (50.0%)	114 (89.8%)	187 (89.9%)	10 (76.9%)	4 (100.0%)	<0.01
Hyperlipidemia	220 (57.9%)	7 (25.0%)	76 (59.8%)	122 (58.7%)	11 (84.6%)	4 (100.0%)	<0.01
Known CAD	109 (28.7%)	2 (7.1%)	39 (30.7%)	59 (28.4%)	6 (46.2%)	3 (75.0%)	0.01
History of MI	46 (12.1%)	1 (3.6%)	10 (7.9%)	29 (13.9%)	5 (38.5%)	1 (25.0%)	<0.01
Congestive Heart Failure	24 (6.3%)	0 (0.0%)	9 (7.1%)	13 (6.3%)	1 (7.7%)	1 (25.0%)	0.35
Tobacco Abuse	230 (60.5%)	10 (35.7%)	67 (52.8%)	140 (67.3%)	10 (76.9%)	3 (75.0%)	<0.01
Diabetes	57 (15.0%)	2 (7.1%)	18 (14.2%)	33 (15.9%)	3 (23.1%)	1(25.0%)	0.64

Table 2: Procedural Indications and Procedures Performed (TAAA: Thoracoabdominal Aortic Aneurysm)

	Procedure Indication				Procedure Performed
	Aneurysm (n=225)	Dissection (n=127)	Transection (n=28)	P-Value	Descending Only Repair (n=288)	Hybrid TAAA Repair (n=65)	Any Arch Involvement (n=27)	P-Value
No Workup	7 (3.1%)	8 (6.3%)	13 (46.4%)	<0.01	26 (9.0%)	1 (1.5%)	1 (3.7%)	<0.01
ECG Only	71 (31.6%)	44 (34.7%)	12 (42.9%)		107 (37.2%)	16 (24.6%)	4 (14.8%)
Echo	131 (58.2%)	75 (59.1%)	2 (7.1%)		145 (50.4%)	42 (64.6%)	21 (77.8%)
Stress Test	12 (5.3%)	0 (0%)	1 (3.4%)		8 (2.3%)	5 (7.7%)	0 (0%)
Coronary Angiography	4 (1.8%)	0 (0%)	0 (0%)		2 (0.7%)	1 (1.5%)	1 (3.7%)

Table 3: Perioperative Characteristics/Outcomes (ASA: American Society of Anesthesiologists)

	All Patients (n=380)	No Workup (n=28)	ECG Only (n=127)	Echo (n=208)	Stress Test (n=13)	Coronary Angiography (n=4)	P-Value
Ejection Fraction	53.1±4.8	54.4±1.8	53.2±3.9	53.1±5.1	51.8±5.1	52.5±3.5	0.84
ASA Class=4	151 (39.7%)	21 (75.0%)	60 (47.2%)	61 (29.3%)	6 (46.2%)	3 (75.0%)	<0.01
Non-Elective Procedure Status	148 (39.0%)	24 (85.7%)	54 (42.5%)	66 (31.7%)	4 (30.8%)	0 (0.0%)	<0.01
Concomitant Procedure or Vessel Bypass (e.g Peripheral Stent or Vessel Bypass)	156 (41.1%)	8 (28.6%)	45 (35.4%)	94 (60.3%)	7 (53.9%)	2 (50.0%)	0.20
Outcomes
30-Day Myocardial Infarction	9 (2.4%)	0 (0%)	1 (0.8%)	8 (3.9%)	0 (0%)	0 (0%)	0.35
30-Day Cardiac Event (MI+ Cardiac Arrest)	9 (2.4%)	0 (0%)	1 (0.8%)	8 (3.9%)	0 (0%)	0 (0%)	0.35
30-Day Cardiac Specific Mortality	3 (0.8%)	0 (0%)	1 (0.8%)	2 (1.0%)	0 (0%)	0 (0%)	0.98
30-Day Mortality	21 (5.5%)	0 (0%)	9 (7.1%)	12 (5.6%)	0 (0%)	0 (0%)	0.52