Wednesday, December 15, 2004

Guidelines: Coronary Artery Bypass Grafting

Guidelines updated for Coronary Artery Bypass Grafting (CABG):

" "Key Points

  1. Off-pump CABG, which avoids aortic cannulation and cardiopulmonary bypass, is now available in many hospitals. However, three randomized trials comparing neurologic outcomes after off-pump and on-pump CABG provide insufficient evidence to warrant the conclusion that the off-pump procedure is better for limiting neurologic complications.
  2. The authors note that long-term data from trials of angioplasty versus CABG (most notably the BARI trial) continue to show significant advantages with CABG for preventing death and repeat revascularization in diabetes patients.
  3. Since 1999, both stent use and left internal mammary-artery grafting have become more common. The most recent randomized trial data show that rates of death, MI, and stroke remain similar for CABG recipients compared with stent recipients. The authors also mention that CABG's advantage over stenting for preventing repeat revascularization has narrowed, but remains significant.
  4. In a class I recommendation, the authors write that aspirin is "the drug of choice" for prophylaxis against early saphenous-vein graft closure and should be continued indefinitely.
  5. There is a new class I recommendation for statin therapy in all CABG patients, unless contraindicated.
  6. Hormone replacement therapy should no longer be initiated in women after CABG.
  7. The new guidelines emphasize the importance of understanding how newer antithrombotic and antiplatelet therapies affect bleeding risk in acute coronary syndrome patients who undergo CABG. For example, the authors have made a class I recommendation that clopidogrel be withheld for 5 days before CABG, if clinical circumstances permit.
  8. Several new sections have been added, including those about off-pump techniques, robotic coronary bypass, and the value of clinical guidelines and pathways for guiding postoperative care and improving outcomes." "

[Via Medscape Headlines]



Friday, December 10, 2004

Recent developments in non-invasive cardiology -- Prasad et al. 329 (7479): 1386 -- BMJ

Recent developments in non-invasive cardiology -- Prasad et al. 329 (7479): 1386 -- BMJ:

"Current clinical applications of cardiovascular magnetic resonance imaging
  • General--measurement of cardiac volume and function; if echocardiography is unsatisfactory
  • Great vessels--accurate sizing; detection of dissection, coarctation, stenosis; anomalous vessels
  • Congenital heart disease--check for concordance of atrioventricular or ventriculoarterial connections; check for great vessels connections; assessment of conduits; assessment of complex anatomy
  • Ischaemic heart disease--detection of regional wall motion abnormalities or infarction; assessment of viability
  • Cardiomyopathy--identification of hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy; detection of fibrosis or scarring; risk stratification; quantification of iron overload in thalassemia
  • Left ventricular mass--accurate assessment in hypertension; assessment of response to therapy
  • Valvular disease--quantification of regurgitation
  • Pericardium--assessment of thickening
  • Cardiac masses--characterisation of tissue; assessment of extent of tumour
"

Parenteral metoclopramide for acute migraine: meta-analysis of randomised controlled trials -- Colman et al. 329 (7479): 1369 -- BMJ

BMJ: Parenteral metoclopramide for acute migraine: meta-analysis of randomised controlled trials -- Colman et al. 329 (7479): 1369

""Conclusions: Metoclopramide is an effective treatment for migraine headache and may be effective when combined with other treatments. Given its non-narcotic and antiemetic properties, metoclopramide should be considered a primary agent in the treatment of acute migraines in emergency departments.""

This works well. I've been using metoclopramide (Reglan) for perioperative migraine for years, ever since learning about it from a Navy ER doc at Balboa. I don't use metoclopramide for post-operative nausea vomiting (prophylactic or treatment), but that's another blog post.



Thursday, December 9, 2004

NEJM -- The Genetic Archaeology of Influenza

NEJM -- The Genetic Archaeology of Influenza:

" "Different strains of influenzavirus have different pathologic effects. For example, infection by the so-called Spanish influenzavirus caused more than 20 million deaths in 1918 and 1919, many of which were due to hemorrhagic pneumonia. To identify the critical components of this virus, mouse-adapted influenza A viruses (Panel A) were modified by Kobasa et al. so that these viruses expressed the form of hemagglutinin encoded by the gene of the 1918 Spanish influenza strain (HAsp), alone (Panel C) or in combination (Panel B) with the form of neuraminidase encoded by the gene of the 1918 Spanish influenza strain (NAsp). They concluded that the HAsp protein is critical to the enhanced cytokine production, inflammation, and hemorrhagic pneumonia that characterized this virulent influenza." "

" "This new study has important clinical and epidemiologic implications. Assuming that the mouse model at least partially reflects the important factors in the virulence of influenza in humans, further dissection of the HAsp molecule is warranted to help identify the critical structural motifs that confer enhanced virulence. This can be accomplished by performing site-directed mutational analyses of the HAsp gene and investigating the effects of these mutations on infection in the mouse model. The identification of these motifs may provide a new epidemiologic tool for surveillance of circulating animal and human influenzaviruses that could be used to predict the emergence of a new, highly virulent pandemic strain. In addition, these detailed molecular studies could facilitate the identification of antigenic epitopes to include in vaccines in order to protect people against related pandemic strains." "

The above comments are in reference to a recent article in Nature titled Enhanced virulence of influenza A viruses with the haemagglutinin of the 1918 pandemic virus. This is exciting and excellent work which opens the way for more fundamental basic science animal research as well as clinical studies.

Military Medicine Is Making A Difference In Iraq

From NEJM: Casualties of War — Military Care for the Wounded from Iraq and Afghanistan

""Though firepower has increased, lethality has decreased. In World War II, 30 percent of the Americans injured in combat died.3 In Vietnam, the proportion dropped to 24 percent. In the war in Iraq and Afghanistan, about 10 percent of those injured have died. At least as many U.S. soldiers have been injured in combat in this war as in the Revolutionary War, the War of 1812, or the first five years of the Vietnam conflict, from 1961 through 1965 (see table). This can no longer be described as a small or contained conflict. But a far larger proportion of soldiers are surviving their injuries.

"It is too early to make a definitive pronouncement that medical care is responsible for this difference. With the war ongoing and still intense, data on the severity of injuries, the care provided, and the outcomes are necessarily fragmentary. But from the data made available for this report and discussions with surgical teams that have returned home, a suggestive picture has emerged. It depicts a military medical system that has made fundamental — and apparently effective — changes in the strategies and systems of battle care, even since the Persian Gulf War.""

And, near the end, this tidbit about updated contingency plans for registration of health care workers:

""Interest in joining the reserves has dropped precipitously. President George W. Bush has flatly declared that there will be no draft. However, the Selective Service, the U.S. agency that maintains draft preparations in case of a national emergency, has recently updated a plan to allow the rapid registration of 3.4 million health care workers 18 to 44 years of age. The Department of Defense has indicated that it will rely on improved financial incentives to attract more medical professionals. Whether this strategy can succeed remains unknown. The pay has never been competitive. One now faces a near-certain likelihood of leaving one's family for duty overseas. And without question, the work is dangerous.""

A former teacher and Army Reserve Anesthesiologist, Rod Calverley, suggested that since the military had become an instrument of foreign policy rather than being used just to protect the homeland, perhaps I should not join the reserves and tend to my young marriage and likely family instead. After 9/11, I think he'd be advising me otherwise...and to put my money where my mouth is.



Wednesday, December 8, 2004

Two NEJM Articles on the War

NEJM: Notes of a Surgeon: Casualties of War — Military Care for the Wounded from Iraq and Afghanistan (free full text)

NEJM: From the War Zone to the United States: Caring for the Wounded in Iraq — A Photo Essay (free full text)



Friday, December 3, 2004

Ten troublesome trends in TV health news

Ten troublesome trends in TV health news:

  1. Too brief to matter
  2. No full time health journalists
  3. No data to back up sensational claims
  4. Hyperbole
  5. Commercialism
  6. Single source stories
  7. Baseless predictions from basic science
  8. FDA approval treated as a fait accompli
  9. Little coverage of health policy
  10. No time for enterprise

[Via bmj.com -- latest BMJ headline]



Wednesday, December 1, 2004

That's Why We Call Them 'Donorcycles'

Picked from Trends in Motorcycle Fatalities Associated with Alcohol-Impaired Driving --- United States, 1983--2003 [CDC]

""Motorcycles are the most dangerous type of motor vehicle to drive. These vehicles are involved in fatal crashes at a rate of 35.0 per 100 million miles of travel, compared with a rate of 1.7 per 100 million miles of travel for passenger cars.""



Monday, November 29, 2004

Cocoa, Flavanols and Cardiovascular Risk

Cocoa, Flavanols and Cardiovascular Risk:

""The Kuna Indians in Panama, living in their indigenous island home in the Caribbean, do not show the typical rise in blood pressure with age, and hypertension is very rare.[34] In a study that began with the search for protective genes, the observation that migration to Panama City led to a loss of the protection against hypertension made it clear that an environmental factor was involved. Examination of their diet uncovered the fact that they drank large volumes of a flavanol-rich cocoa.[2] Subsequent in vitro studies suggesting that cocoa extracts can induce endothelium-dependent relaxation[4] led to studies in healthy volunteers,[9] and in patients with vascular risk or disease.[1] In the studies of Heiss et al. ingestion of flavanol-rich cocoa led to an increase in flow-mediated vasodilation of the brachial artery following five minutes of ischaemia, a response that correlated with biochemical evidence of increased nitric oxide bioavailability.[8] In the normal volunteers studied by Fisher et al. flavanol-rich cocoa induced striking dilatation of the vessels of the finger, which was reversed completely by an arginine analogue that blocks nitric oxide synthesis (figure 1).[9]""

and

""Endothelial dysfunction with a consequent reduction in nitric oxide production has achieved a central conceptual role in the pathogenesis of atherosclerosis and coronary artery disease, diabetes mellitus and hypertension. Recent evidence that flavanol-rich cocoa activates vascular nitric oxide synthesis in the intact human raises an interesting possibility of a therapeutic potential.""

Potentially very good news for Hershey foods, what, what?

[Via Medscape Headlines]

Abortion Surveillance --- United States, 2001

Abortion Surveillance --- United States, 2001:

""A total of 853,485 legal induced abortions were reported to CDC for 2001 from 49 reporting areas, representing a 0.5% decrease from the 857,475 legal induced abortions reported by the same 49 reporting areas for 2000. The abortion ratio, defined as the number of abortions per 1,000 live births, was 246 in 2001, compared with 245 reported for 2000. This represents a 0.4% increase in the abortion ratio. The abortion rate was 16 per 1,000 women aged 15--44 years for 2001, the same as for 2000. For both the 48 and 49 reporting areas, the abortion rate remained relatively constant during 1997--2001.""

These numbers exclude Alaska, California, and New Hampshire.

I post this not because I am anti-choice, but because I was surprised by the abortion ratio of 246 abortions per 1,000 live births--much higher than I would have guessed. My sincere (but admittedly naive) hope is that abortions are not being relied on as a means of birth control.

[Via MMWR]



Saturday, November 27, 2004

Lancet: Risk of cardiovascular events and rofecoxib

Lancet: Risk of cardiovascular events and rofecoxib: cumulative meta-analysis (pdf)

""Findings: We identified 18 randomised controlled trials and 11 observational studies. By the end of 2000 (52 myocardial infarctions, 20742 patients) the relative risk from randomised controlled trials was 2·30 (95% CI 1·22-4·33, p=0·010), and 1 year later (64 events, 21432 patients) it was 2·24 (1·24-4·02, p=0·007). There was little evidence that the relative risk differed depending on the control group (placebo, non-naproxen NSAID, or naproxen; p=0·41) or trial duration (p=0·82). In observational studies, the cardioprotective effect of naproxen was small (combined estimate 0·86 [95% CI 0·75-0·99]) and could not have explained the findings of the VIGOR trial.""



Friday, November 26, 2004

Making The Flu Vaccine Go Further

NEJM: Dose Sparing with Intradermal Injection of Influenza Vaccine (free full text)

NEJM: Serum Antibody Responses after Intradermal Vaccination against Influenza (free full text)



Tuesday, November 23, 2004

New Female Sterilization Technique Quicker, Easier and Cheaper

New Female Sterilization Technique Quicker, Easier and Cheaper:

""Mayo Clinic gynecologists have discovered that hysteroscopic sterilization, a new method of plugging the fallopian tubes to prevent conception, will save patients money compared to laparoscopic tubal ligation, the most commonly used method of sterilization for women. This technique involves inserting a nickel-titanium and stainless steel springlike device into the fallopian tubes using a hysteroscope, a tiny, fiberoptic camera. The metal device encapsulates and holds in place white polyester fibers able to cause scarring and thus block the fallopian tubes within 12 weeks, preventing the possibility of future pregnancy.""

Of course, it's still not as easy as a man having a vasectomy, but this technique would not require laparoscopy and would thus be safer for the woman.

[Via Science Blog - Science News Stories]

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