Eur J Cardiothorac Surg 2004;25:231-235
© 2004 Elsevier Science NL
The role of coronary angiography in acute type A aortic dissection
Reza Motallebzadeha,
Divna Batasa,
Oswaldo Valenciaa,
Venkatachalam Chandrasekarana,
John Smitha,
Stephen Breckerb,
Marjan Jahangiria*
a Department of Cardiac Surgery, St George's Hospital and Medical School, Blackshaw Road, London SW17 0QT, UK
b Department of Cardiology, St George's Hospital and Medical School, London UK
Received 9 September 2003;
received in revised form 24 October 2003;
accepted 12 November 2003.
* Corresponding author. Tel.: +44-20-8725-3565; fax: +44-20-8725-2049
e-mail: marjan.jahangiri{at}stgeorges.nhs.uk
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Abstract
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Objectives: In recent years, non-invasive methods have replaced angiography in the diagnosis of aortic dissection. Angiography maybe used to evaluate coexisting coronary artery disease (CAD), which can delay surgery and increase the risk of rupture. We set out to examine the role of angiography in acute aortic dissection. Methods: A retrospective analysis of patients who underwent repair of acute aortic dissection between January 1992 and June 2002 was conducted. The effect of angiography on the need for concomitant coronary artery surgery (CABG), delay to surgery and outcome were analysed. Results: Seventy-four patients were identified. Initial diagnosis was established by non-invasive techniques. Twenty-three patients (31%) underwent angiography (Group I) in three this was unsuccessful. Three in Group I and four in the non-angiography group (Group II, n=51) had history of angina. One patient in Group I underwent concomitant CABG compared to seven in Group II. The patient who underwent CABG in Group I; and four out of seven in Group II died (NS). Patients who underwent concomitant CABG had a significantly higher mortality rate (P=0.04). Mortality in Group I was 35% (n=8) and in Group II was 29% (n=15) (NS). Mortality rate was also significantly higher in patients who presented with syncope (P=0.01) or hypotension (P=0.04). Median transfer time from arrival at our centre to the operating room was 5 h in Group I and 1.5 h in Group II (P<0.001). Mortality rate was higher in patients who took longer to transfer to the operating room, but this did not reach statistical significance. Conclusions: We have shown that coronary angiography did not affect the occurrence of CABG and was not associated with improved hospital survival. Furthermore, there is a considerable delay to surgery caused by angiography. Therefore in this setting coronary angiography is not recommended.
Key Words: Angiography • Aortic dissection
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1. Introduction
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Acute aortic dissection is a life threatening emergency which requires quick and accurate diagnosis in order to facilitate successful treatment. The mortality in patients who do not receive surgical treatment is as high as 40% on the first day and 70% within one week [1].
Patients presenting with acute aortic dissection often share the same risk factors for coronary artery disease (CAD). In a post-mortem study of 161 cases of aortic dissection, it was found that 25% of cases had evidence of severe coronary atherosclerosis [2]. This has important implications for the method of diagnosis and subsequent surgical management of acute aortic dissection, especially in the elderly. Transesophageal echocardiography (TEE) can only delineate the coronary ostia and proximal portion of the coronary arteries. Its role is essentially limited to identifying whether the dissection extends into the coronary vessels [3]. Hence, in order to detect coronary atherosclerosis, which is usually more distal, coronary angiography would be required. Coronary angiography in this setting is not without risks. Besides potentially extending the dissection by advancing the catheter into the false lumen, or exacerbating renal insufficiency by use of contrast agents, there will be a significant delay before surgery can commence [4,5]. Furthermore, if the dissection involves the coronary arteries, it will not be possible to perform coronary angiography from the true lumen.
There are conflicting reports in the literature as to whether coronary angiography is indicated in the setting of aortic dissection and what effect it has on postoperative mortality [6–8]. Furthermore as outlined in the ACC/AHA guidelines, there is no clear consensus on the need for coronary angiography before surgical intervention of acute aortic dissection [9]. We therefore set out to examine the effect of coronary angiography on the need for concomitant CABG, delay to surgery, and morbidity and mortality in patients presenting with acute dissection of the ascending aorta.
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2. Material and methods
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A retrospective analysis of patients who underwent surgery for acute aortic dissection between January 1992 and June 2002 was carried out. Seventy-four patients were identified. Baseline characteristics including age, sex, history of hypertension, angina, myocardial infarction (MI), smoking, diabetes, peripheral vascular disease, stroke or transient ischemic attack, previous cardiac surgery and Marfan's syndrome were recorded (Table 1).
All the patients had initially presented to their local hospital and were transferred to our unit for further investigation and definitive management. In all patients the diagnosis was made by non-invasive methods, including CT scan and/or echocardiography (Table 2). The diagnosis of acute dissection of the ascending aorta was based on the presence of an intimal flap within the ascending aorta. Other supporting features included identification of two distinct lumens, tear entry site, aortic root dilatation and aortic valve insufficiency. An assessment of left ventricular function was made by echocardiography. There had been no written protocol for the need for coronary angiography. This was performed according to the practice of the cardiologist and the surgeon on duty and on an individual patient based decision. It was performed more commonly in the earlier part of the study. Twenty-three patients (31%) underwent coronary angiography (Group I) and 51 patients (69%) did not have this investigation (Group II). Angiography was performed to assess CAD (selective) and/or to confirm the presence of an intimal flap (non-selective).
The following data were analysed: clinical presentation including features such as hypotension, defined by a systolic blood pressure of less than 90 mmHg, aortic regurgitation of moderate or severe degree, ECG evidence of ischemia, (Table 3), time from arrival at our centre to the operating room, operative technique (Table 4), and postoperative morbidity and mortality (Table 5).
2.1. Surgical techniques
Cardiopulmonary bypass was established by cannulation of the femoral artery and right atrium. If the aortic root was normal, the ascending aorta was replaced with a tubular graft. If the sinuses and aortic valve could not be preserved, a complete root replacement using a composite graft or a separate valve and graft was performed. Aortic valve suspension was carried out if the valve could be preserved. Patients underwent concomitant CABG if the dissection extended along the coronary arteries or if there were signs of ischemia following repair of dissection and involvement of the coronary arteries was suspected, and in the presence of significant CAD identified preoperatively (Table 4).
2.2. Statistical analysis
All statistics was performed using SPSS version 11.0 for Windows (SPSS, Chicago, IL). Categorical variables are expressed as number (percent) and continuous variables are represented as mean±SD. Mann–Whitney tests were used to compare non-normally distributed variables. Categorical variables were analysed by 
2 or Fisher's exact tests. Selected variables were entered into multivariate analysis by a stepwise logistic regression technique to determine independent predictors of mortality.
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3. Results
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There were no significant differences in the baseline characteristics between the two groups (Table 1). In both groups the most frequent symptom on presentation was chest pain. Cardiac tamponade, aortic regurgitation and ECG signs of ischemia were more common in Group II (Table 3). The diagnosis of dissection was made mostly by transthoracic echocardiography (TTE) in Group I (73.9%) and by CT scan in Group II (72.5%) (Table 2).
Three patients in Group I and four patients in Group II had a history of angina. Fig. 1
summarises the results of angiography. Angiography had to be aborted because of hemodynamic instability in one patient in the selective angiography subgroup and in two patients in the non-selective subgroup. Four patients (17.4%) had evidence of CAD.
In both groups, the median time from symptom onset to arrival at our unit was 6 h (range 4–24 and 4–15 h in groups I and II, respectively). However, the median time from arrival to operating room was 5 h (range 3–9 h) in Group I and 1.5 h (range 1–4 h) in Group II (P=0.0007).
One patient in Group I underwent concomitant CABG. In the other three patients with CAD diagnosed by angiography, CABG was not carried out due to moderate extent of the disease. Seven patients in Group II had concomitant CABG, but in four of these the additional surgery was performed due to dissection of the proximal portion of the right coronary artery. In the remaining patients CABG was undertaken ‘blindly’, that is in patients who showed intraoperative ischemic ECG changes and failed to wean off cardiopulmonary bypass, possibly due to underlying CAD. Of all those who underwent CABG, only two patients had a history of angina (Fig. 1).
The overall mortality was 35% (8/23) in Group I and 29% (15/51) in Group II. There were no preoperative deaths in Group II. With reference to patients who underwent concomitant CABG, the single patient in Group I and four out of seven in Group II died. As shown in Table 6, the in-hospital mortality rate was significantly higher in patients who presented with a history of syncope or hypotension and in patients who underwent concomitant CABG. After controlling for confounding factors, only a history of syncope remained an independent predictor of in-hospital mortality (odds ratio [OR] 3.8; 95% confidence interval 1.3–11.0, P=0.07).
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4. Discussion
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Coronary angiography may be indicated in patients with aortic dissection to detect CAD. Although 26 (35%) patients showed evidence of ischemia on ECG, a number similar to that found in previous studies [10], angiography was positive for CAD in only four patients. Other studies have also shown that there is a relatively low incidence of CAD in such patients [11–13]. Hence, even though aortic dissection and coronary atherosclerosis share risk factors such as hypertension, the pathophysiologic processes are fundamentally different and therefore one should not necessarily expect patients presenting with aortic dissection to have underlying CAD [14].
Patients who underwent coronary angiography had a significant delay before being transferred to the operating room. This is accounted for by the time taken to assemble relevant staff, transferring the patient to the angiography suite and by the procedure itself. The delay resulted in higher in-hospital mortality, although it did not reach statistical significance, possibly due to the small numbers in the study. However, previous studies have shown that angiography and the delay in definitive treatment can result in aortic rupture and death [11].
Because only one patient had a history of MI in this series, we cannot comment on the impact of coronary angiography on in-hospital mortality in patients with a history of MI. However, Penn and colleagues showed that coronary angiography had no effect on in-hospital mortality in patients with a history of MI [7].
Patients who underwent concomitant CABG did not fare well as the mortality in these patients was significantly higher. These patients had longer cardiopulmonary bypass times, but this was probably not the only factor to account for the high mortality. Ischemic myocardium due to dissection of coronary arteries, rather than atherosclerotic CAD, could have been an important contributing factor. Preoperative coronary angiography was not performed in the three patients who underwent concomitant CABG ‘blindly,’ (i.e. due to ischemic ECG changes intraoperatively). These patients were hypotensive and hemodynamically unstable at presentation, and it was felt that coronary angiography in this setting would have been a considerable risk. The overall postoperative mortality is similar to that found in reported studies, ranging from 18 to 33% [7,8,15–17].
In conclusion, the results from this study do not support the use of routine coronary angiography in patients with acute aortic dissection. The low incidence of CAD in these patients and the significant delay that results from performing angiography do not support this investigation. In this study we have demonstrated that performing preoperative coronary angiography did not alter our surgical management, as only one patient in the angiography group proceeded to concomitant CABG. It is difficult to decide which group of patients might benefit from preoperative coronary angiography. As this study shows even a history of angina is not necessarily an accurate guide for deciding which patients have significant CAD to warrant concomitant CABG. We have shown that coronary angiography did not affect the incidence of CABG and was not associated with improved hospital survival. An alternative strategy might be to conduct intraoperative angiography to detect CAD, but this is not readily available in most centres. However, techniques employing intraoperative ultrasound and thermal angiography might be increasingly used to detect CAD intraoperatively [18–20]. Alternatively, multi slice high definition CT scans (MSCT) could allow simultaneous diagnosis of aortic dissection and CAD [21]. MSCT can image the vessel lumen and has the ability to visualise the coronary artery wall. In this way, valuable time could be saved with regards to the preoperative work up and additional CABG surgery can then be performed on appropriate patients.
4.1. Limitations of the study
As this is a retrospective study, there is concern that uncontrolled and confounding variables such as the effect of different operating surgeons over the study period and different severity of clinical presentation, could have influenced our results. The alternative would be to conduct a randomised study of angiography versus no angiography. As the incidence of type A aortic dissection is only in the region of 5–10 per one million population, a well powered randomised study would require many centers participating in a trial lasting for many years.
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Acknowledgments
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We would like to thank Professor T Treasure, Mr A Murday and Mr J Gaer for allowing us to use their patients in this study.
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Abstract
1. Introduction
