Archive for the ‘Articles’ Category

Surgery shortly after an MI still contraindicated?

Thursday, May 12th, 2011

An administrative database from the state of California suggests that surgery in the first month after an MI greatly increased the chances of reinfarction, and significantly increased the risk of death.  Vascular patients actually had lower RRs than other NCS, suggesting that the atherosclerotic burden is more uniformly increased in vascular patients compared to others (hips, colon resection), or that clinicians were more careful and/or attuned to caring for the vascular patients.

RESULTS: Postoperative MI rate for the recent MI cohort decreased substantially as the legth of time from MI to operation increased (0-30 days = 32.8%, 31-60 days = 18.7%, 61-90 days = 8.4%, and 91-180 days = 5.9%), as did 30-day mortality (0-30 days = 14.2%, 31-60 days = 11.5%, 61-90 days = 10.5%, and 91-180 days = 9.9%). MI within 30 days of an operation was associated with a higher risk of postoperative MI (RR range = 9.98-44.29 for the 5 procedures), 30-day mortality (RR range, 1.83-3.84), and 1-year mortality (RR range, 1.56-3.14).

CONCLUSIONS: A recent MI remains a significant risk factor for postoperative MI and mortality following surgery. Strategies such as delaying elective operations for at least 8 weeks and medical optimization should be considered

Many things have changed since Rao and El-Etr‘s classic paper:

  • TnI and CKMB are much more sensitive and more likely to be used as a screening tool than simply after symptoms occur.  Therefore, we suspect that the MIs detected in th 21st century may be smaller than in the past, but more prevalent.
  • PCI and more optimal medical Rx are available today, which might reduce the likelihood and lethality of reinfarction

The authors did not address the impact of medical Rx nor revascularization in this study.  However, the same group (least publishable units?) published another paper suggested that preop PCI or CABG protects against reinfarction.   They state:

Patients with a recent MI who were revascularized before surgery had an approximately 50% decreased rate of reinfarction (5.1% versus 10.0%; p < 0.001) and 30-day (5.2% versus 11.3%; p < 0.001) and 1-year mortality (18.3% versus 35.8%; p < 0.001) compared with those who were not. Stenting within 1 month of surgery was associated with a trend toward increased reinfarction (relative risk: 1.36; 95% CI, 0.96-1.97), and coronary artery bypass graft was associated with a decreased risk (relative risk: 0.70; 95% CI, 0.55-0.95).

Again, there are selection biases:

  • Emergent cases are probably too sick to wait for revascularization.
  • Some sick/frail patients may not be felt to be good candidates for revascularization.

In fact, only ~12% of revascularizations occurred in the 3 months before surgery.  At surgery < 1 month after original MI, reinfarction rates were high (~1/3) and no lower in the revascularization group.

For patients undergoing vascular surgery, early revascularization (within 1 month of MI) was associated with lower reinfarction rates compared with no revascularization (21.3% versus 34.2%; p = 0.026). In contrast, for those undergoing nonvascular surgery, reinfarction rates were greater for revascularized patients (40.4% versus 31.6%; p = 0.038). Patients undergoing vascular surgery were more likely to receive CABG than PTCA (53.7% versus 46.3%), but the reverse was true for nonvascular surgery (41.2% versus 58.8%) (p < 0.001). This pattern of revascularization was also seen for patients undergoing surgery within 1 month of MI (vascular: 43.8% CABG versus 56.3% PTCA; nonvascular: 32.9% CABG versus 67.1% PTCA; p = 0.10).

Lastly, the authors mention that the CARP trial did not show survival benefits for coronary revascularization before vascular surgery, but did suggest lower rates of MI after CABG than PCI, as these authors have also shown.

The debates continue!

“Influence of Psychiatric Comorbidity on Surgical Mortality”

Monday, November 1st, 2010

This study in Arch Surg confirms my biases – that depression and anxiety increase mortality after major surgery.  These patients at the Iowa VA did not all undergo vascular surgery, but the patient population is very similar (see Table below)

Transfusion in cardiac surgery – a crap shoot that doesn’t affect outcome?

Wednesday, October 13th, 2010

Two articles in JAMA document that:

  • Transfusion practices vary tremendously amongst institutions…
    • “Results At hospitals performing at least 100 on-pump CABG operations (82 446 cases at 408 sites), the rates of blood transfusion ranged from 7.8% to 92.8% for RBCs, 0% to 97.5% for fresh-frozen plasma, and 0.4% to 90.4% for platelets. Multivariable analysis including data from all 798 sites (102470 cases) revealed that after adjustment for patient-level risk factors, hospital transfusion rates varied by geographic location (P = .007), academic status (P = .03), and hospital volume (P < .001). However, these 3 hospital characteristics combined only explained 11.1% of the variation in hospital risk-adjusted RBC usage. Case mix explained 20.1% of the variation between hospitals in RBC usage.”
  • After cardiac surgery, a restrictive transfusion strategy (Hgb 9.1) appears to result in equivalent outcomes compared to a liberal one (Hgb 10.5)….
    • “The TRACS Randomized Controlled Trial… Conclusion Among patients undergoing cardiac surgery, the use of a restrictive perioperative transfusion strategy compared with a more liberal strategy resulted in noninferior rates of the combined outcome of 30-day all-cause mortality and severe morbidity.”

New ACC Thoracic Aortic guidelines: CSF drains; changing DLETT at the end of surgery

Monday, July 5th, 2010

The guidelines can be downloaded from the Web site

Anesthesiology News notes, regarding CSF drains:

In particular, the recommended strategy for spinal cord protection during descending aortic open surgical and endovascular repair is likely to change practice, according to David Reich, MD, professor and chair of anesthesiology at Mount Sinai School of Medicine in New York City. The class I recommendation (section 14.5.2) states that in patients at high risk for spinal cord ischemic injury, drainage of cerebrospinal fluid (CSF) protects the spinal cord.

Dr. Reich said the key phrase in the recommendation is patients at high risk for spinal cord ischemic injury. “That’s new,” he said. “Clinicians will be concerned as to determining what constitutes high risk, and what will happen if they did not do CSF drainage in a patient who is paralyzed postoperatively.” He said that the definition of high risk is fairly well defined in the surgical literature.

Anesthesiology News notes, regarding changing a double lumen ETT at the end of the case:

Another recommendation that affects anesthesiologists is found in section 14.2: The routine changing of double-lumen endotracheal (endobronchial) tubes to single-lumen tubes at the end of surgical procedures complicated by significant upper airway edema or hemorrhage is not recommended. According to Dr. Reich, this recommendation is based on expert opinion (level of evidence classified as C).

CSF drains are not without complications of course.

I have seen emergent tracheostomy, and poor outcome, after airway obstruction following removal of a DLETT.  One approach could be to start with a Univent or bronchial blocker, with possibly less secure lung separation.  Another is to cut the distal balloon on the DLETT left in place to minimize malposition problems in the ICU.  Never an easy decision.