Should the ACC/AHA guidelines be changed in patients undergoing vascular surgery?

Sanne E. Hoeks1, Jeroen J. Bax2 and Don Poldermans1,*

1Department of Cardiology, Thoraxcenter Room H921, Erasmus MC, Dr Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
2Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands

* Corresponding author. Tel: +31 10 4634613; fax: +31 10 4634957. E-mail address: d.poldermans{at}erasmusmc.nl

This editorial refers to ‘Vascular surgery patients: perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin evaluation’{dagger} by F. Bursi et al., on page 2448

In western countries, annually about 4–10% of the population is scheduled for non-cardiac surgery. Patients undergoing vascular surgery are known to be at increased risk of peri-operative mortality and other cardiac complications due to underlying (a)-symptomatic coronary artery disease (CAD). Although the overall peri-operative event rate has declined over the past 30 years, 30-day cardiovascular mortality still remains as high as 3–5%.1 Myocardial infarction (MI) accounts for 10–40% of post-operative fatalities and can therefore be considered as the major determinant of peri-operative mortality associated with non-cardiac surgery.2

The pathophysiology of a peri-operative MI (PMI) is not entirely clear. However, similar to MIs occurring in the non-operative setting, coronary plaque rupture, leading to thrombus formation and subsequent vessel occlusion is suggested as an important causative mechanism.2 Surgery is an important stress factor leading to an increase in the incidence of plaque rupture. In patients with significant CAD, PMI may also be caused by a sustained myocardial supply/demand imbalance due to prolonged haemodynamic stress inducing sustained myocardial ischaemia. Both factors, acute thrombus formation and sustained myocardial ischaemia, probably contribute equally to the pathophysiology of PMI.

In order to improve post-operative outcome, the ACC/AHA developed guidelines for pre-operative cardiac risk evaluation.3 They provide an algorithm for a stepwise approach. Patients are divided into three groups; those who underwent a previous coronary revascularization, previous cardiac testing, and all other remaining patients. If patients underwent a coronary revascularization in the past 5 years and if the clinical status has remained stable without recurrent symptoms or signs of myocardial ischaemia, further cardiac testing is not indicated and the patient can directly send for surgery. Similarly, patients who underwent non-invasive testing or coronary angiography in the past 2 years, in the absence of unfavourable results and without new symptoms, can also send for surgery without further evaluation. All other patients are analysed according to the presence of major, intermediate, and minor clinical risk factors (Table 1) and by addition of procedural risk the individual risk can be assessed. In patients with major risk factors, surgery should be post-poned until these symptoms are adequately treated. Patients with no or only minor risk predictors represent a low-risk population and further evaluation is only necessary for those with a poor functional capacity undergoing vascular surgery. However, in patients with intermediate risk predictors, additional non-invasive evaluation is recommended to assess the presence of myocardial ischaemia and to determine further peri-operative management.


View this table:
[in this window]
[in a new window]
 
Table 1 Clinical predictors of increased peri-operative cardiovascular risk3
 
The present study of Bursi et al.4 reported that despite pre-operative risk stratification according to the ACC/AHA guidelines, patients undergoing elective major vascular surgery are still at high risk of MI and death. Event rates were as high as 45, 23 and 9% in patients with previous revascularization without recurrent symptoms or signs of CAD, with intermediate, and those with minor or no clinical predictors, respectively. These findings question the current recommendations and, moreover, indicate that the ACC/AHA guidelines are of limited use to pre-operative risk stratification in vascular surgery patients.

The high event rates (45%) in a small subpopulation of patients who underwent previous revascularization without signs of CAD, might be explained by an incomplete or failed revascularization or silent ischaemia. These pitfalls should be taken into account when stratifying these patients. In addition, it should be noted that atherosclerosis is an ongoing disease and that plaque progression and vulnerability is unpredictable and is responsible for 50% of all PMIs. This also has important implications for the current guideline stating that the subgroup of patients who have undergone (non-)invasive coronary evaluation in the past 2 years, in the absence of unfavourable stress test results or changes of symptoms, can undergo surgery without further evaluation. Because of the unpredictable character of CAD, this 2-year time lap may be much too long.

The high event rates in patients with minor or intermediate risk factors can partly be explained by change of more sensitive diagnostic tools for PMI over time. Nowadays, diagnosis of PMI requires a rise and fall of troponin with or without clinical or ECG findings, while in the past ECG abnormalities, CK/CK-MB changes, and clinical symptoms indicated a PMI. This resulted in a substantial increase of patients being diagnosed as having MI as also seen in the current study of Bursi et al.4 Prior studies have questioned the value of a positive troponin in the peri- operative setting and even suggested a false positive value especially in patients with renal insufficiency or massive CK enzyme release. However, a recent study confirmed the prognostic value of troponin elevations in post-operative patients.5 Same results were demonstrated in the current paper of Bursi et al.4 which showed that cTnI elevations were independent predictors of subsequent death and/or MI.

Available data suggest that beta-blockers may be underused and yet unpublished results from a survey in the Netherlands also show only 60% use of beta-blockers during vascular surgery.6 In the present study, only 62% of patients with intermediate clinical risk received a peri- operative beta-blocker which may adversely influence outcome. Statins and beta-blockers use may reduce those devastating complications associated with non-cardiac surgery.7,8 Statins may prevent plaque instability and thrombosis, due to their pleiotropic effects, as improvement of endothelial function, reduction of inflammation, and stabilizing atherosclerotic plaques. Beta-blockers can restore the supply/demand mismatch, by the reduction of myocardial oxygen use by decreasing sympathetic tone and myocardial contractility. When beta-blockers are used in the peri-operative period, timing and dose adjustment for heart rate control is important as shown by Raby et al.9 Furthermore, treatment should not be interrupted during the peri-operative period and prolonging beta-blocker therapy beyond the surgical procedure seems to be essential, as the risk of MI remains high in the first post-operative week. Besides beta-blockers and statins, aspirin might be considered to provide optimal medical therapy.

Should the ACC/AHA guidelines be changed in patients undergoing vascular surgery?

Vascular surgery patients probably represent the highest risk population because of the underlying CAD. Basically, the stepwise approach of the guidelines is valid for pre- operative cardiac screening. However, considering previous findings, we would like to give the following recommendations:

  1. The warranty of previous revascularization might be questioned and therefore risk stratification should be considered independently of previous coronary revascularization.
  2. Following the recent publication of Lindenauer et al.,10 beta-blocker therapy appeared to be harmful in low-risk patients, neutral in patients at intermediate risk, and beneficial in high-risk patients.10 This further strengthens the beneficial effects of beta-blockers in high-risk patients and therefore we recommend initiation of beta-blocker therapy in vascular surgery patients. Adjustment of beta-blocker dose is recommended to assure a heart rate between 60–70 b.p.m.
  3. In addition, until the results of DECREASE-II are available, which studies the effect of non-invasive screening in patients undergoing vascular surgery without any or few cardiac risk factors, we believe it is appropriate to screen non-invasively all vascular surgery patients, including carotid surgery, for myocardial ischaemia. Recently, the CARP trial demonstrated that coronary revascularization before elective vascular surgery did not significantly alter the incidence of PMI among patients with stable CAD.11 Therefore, screening of high-risk patients for ischaemia is not essential for revascularization but primary to optimize peri-operative patient management, which includes optimal medical therapy with beta-blockers and statins, monitoring and aggressive treatment of myocardial ischaemia, and if possible endovascular treatment. In patients with exclusion criteria of the CARP trial, >50% stenosis of the left main coronary artery, left ventricular ejection fraction <20%, and severe valvular aortic stenosis, the optimal pre-operative treatment is yet not defined and treatment should therefore be individualized using a combination of minimal invasive surgery in combination with medical therapy and coronary revascularization, if post-ponement of the index surgery can be accepted.

Conflict of interest: none declared.

Footnotes

The opinions expressed in this article are not necessarily those of the Editors of the European Heart Journal or of the European Society of Cardiology.

{dagger} doi:10.1093/eurheartj/ehi430 Back

References

  1. Mangano DT. Perioperative cardiac morbidity. Anesthesiology 1990;72:153–184.[ISI][Medline]
  2. Dawood MM, Gutpa DK, Southern J, Walia A, Atkinson JB, Eagle KA. Pathology of fatal perioperative myocardial infarction: implications regarding pathophysiology and prevention. Int J Cardiol 1996;57:37–44.[CrossRef][ISI][Medline]
  3. Eagle KA, Berger PB, Calkins H, Chaitman BR, Ewy GA, Fleischmann KE, Fleisher LA, Froehlich JB, Gusberg RJ, Leppo JA, Ryan T, Schlant RC, Winters WL Jr, Gibbons RJ, Antman EM, Alpert JS, Faxon DP, Fuster V, Gregoratos G, Jacobs AK, Hiratzka LF, Russell RO, Smith SC Jr. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J Am Coll Cardiol 2002;39:542–553.[Free Full Text]
  4. Bursi F, Babuin L, Barbieri A, Politi L, Zennaro M, Grimaldi T, Rumolo A, Gargiulo M, Stella A, Grazia Modena M, Jaffe AS. Vascular surgery patients: perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin elevation. Eur Heart J 2005;26:2448–2456. First published on July 29, 2005, doi:10.1093/eurheartj/ehi430.[Abstract/Free Full Text]
  5. Kim LJ, Martinez EA, Faraday N, Dorman T, Fleisher LA, Perler BA, Williams GM, Chan D, Pronovost PJ. Cardiac troponin I predicts short-term mortality in vascular surgery patients. Circulation 2002;106:2366–2371.[Abstract/Free Full Text]
  6. Schmidt M, Lindenauer PK, Fitzgerald JL, Benjamin EM. Forecasting the impact of a clinical practice guideline for perioperative beta-blockers to reduce cardiovascular morbidity and mortality. Arch Intern Med 2002;162:63–69.[Abstract/Free Full Text]
  7. Poldermans D, Bax JJ, Kertai MD, Krenning B, Westerhout CM, Schinkel AF, Thomson IR, Lansberg PJ, Fleisher LA, Klein J, van Urk H, Roelandt JR, Boersma E. Statins are associated with a reduced incidence of perioperative mortality in patients undergoing major noncardiac vascular surgery. Circulation 2003;107:1848–1851.[Abstract/Free Full Text]
  8. Poldermans D, Boersma E, Bax JJ, Thomson IR, van de Ven LL, Blankensteijn JD, Baars HF, Yo TI, Trocino G, Vigna C, Roelandt JR, van Urk H. The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography Study Group. N Engl J Med 1999;341:1789–1794.[Abstract/Free Full Text]
  9. Raby KE, Brull SJ, Timimi F, Akhtar S, Rosenbaum S, Naimi C, Whittemore AD. The effect of heart rate control on myocardial ischemia among high-risk patients after vascular surgery. Anesth Analg 1999;88:477–482.[Abstract/Free Full Text]
  10. Lindenauer PK, Pekow P, Wang K, Mamidi DK, Gutierrez B, Benjamin EM. Perioperative beta-blocker therapy and mortality after major noncardiac surgery. N Engl J Med 2005;353:349–361.[Abstract/Free Full Text]
  11. McFalls EO, Ward HB, Moritz TE, Goldman S, Krupski WC, Littooy F, Pierpont G, Santilli S, Rapp J, Hattler B, Shunk K, Jaenicke C, Thottapurathu L, Ellis N, Reda DJ, Henderson WG. Coronary-artery revascularization before elective major vascular surgery. N Engl J Med 2004;351:2795–2804.[Abstract/Free Full Text]

Related articles in EHJ:

Vascular surgery patients: perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin elevation
Francesca Bursi, Luciano Babuin, Andrea Barbieri, Luigi Politi, Mauro Zennaro, Teresa Grimaldi, Antonio Rumolo, Mauro Gargiulo, Andrea Stella, Maria Grazia Modena, and Allan S. Jaffe
EHJ 2005 26: 2448-2456. [Abstract] [Full Text]  




This Article
Full Text (PDF)
All Versions of this Article:
26/22/2358    most recent
ehi510v1
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Related articles in EHJ
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Request Permissions
Google Scholar
Articles by Hoeks, S. E.
Articles by Poldermans, D.
PubMed
PubMed Citation
Articles by Hoeks, S. E.
Articles by Poldermans, D.