Heavy smoking and smoke inhalation linked to poor prognosis after a heart attack

Heavy smoking and smoke inhalation linked to poor prognosis after a heart attack

The risk of death or poor prognosis after a heart attack is more than 20 times higher in smokers with exhaled carbon monoxide levels above 13 parts per million, indicating heavy smoking and smoke inhalation. This is the result of current research results that were presented at the ESC Congress 2022.

The amount of carbon monoxide in your breath is directly related to the number of cigarettes you smoke, but also to the way you smoke. Individuals may inhale smoke heavily or not at all, and they may either smoke cigarettes from start to finish or leave the cigarettes burning in the ashtray. Finally, the place where one smokes can play a crucial role; Smoking in a small, unventilated room is likely to increase carbon monoxide levels compared to smoking outdoors.”

Professor Patrick Henry, Director of Studies, Hospital Lariboisiere, Paris, France

Combustion of cigarettes produces carbon monoxide, a highly toxic gas also found in automobile exhaust, pollution, and malfunctioning furnaces. Carbon monoxide replaces oxygen in the blood and can be fatal. Professor Henry said: "Patients with acute cardiac events such as heart attacks have too little oxygen in their coronary arteries. We hypothesized that the event could be more serious if some of the oxygen was replaced with carbon monoxide."

During a two-week period in April 2021, expiratory carbon monoxide was measured within two hours of admission in all consecutive adults hospitalized for acute cardiac events in 39 intensive care units (ICCU) in France. A total of 1,379 patients were examined. The average age was 63 years and 70% were men. The reason for admission was 720 (52%) patients with acute coronary syndrome, 186 (13%) with acute heart failure and 473 (34%) with other acute heart diseases. The median stay in the intensive care unit was five days.

The patients were asked about their smoking status. A third of participants (33%) were non-smokers, 39% were former smokers and 27% were current smokers. Carbon monoxide levels were similar in non-smokers and former smokers (mean 3.6 and 3.3 ppm, respectively; p = 0.12) and significantly higher in active smokers (mean 9.9 ppm; p < 0.001).

Researchers analyzed the association between carbon monoxide levels and the primary outcome of serious in-hospital adverse events, which was death, resuscitated cardiac arrest, or cardiogenic shock. A total of 58 (4.2%) patients experienced serious adverse events in the hospital. Carbon monoxide levels were significantly associated with serious adverse events in active smokers, with an odds ratio of 1.14 per unit ppm, meaning that for every one ppm increase in carbon monoxide levels there was a 14% higher chance of an event.

The researchers identified 13 ppm as the best threshold for predicting a worse prognosis. The odds of a serious adverse event were 23 times higher in smokers with carbon monoxide levels above 13 ppm than with 13 ppm or below, after adjusting for factors that could influence the relationship, including age, gender, diabetes, smoking status, history of cardiovascular disease, chronic kidney disease, history of cancer and reason for admission. In smokers with carbon monoxide levels of 13 ppm or less, the rate of serious adverse events was similar to that in non-smokers or former smokers (p = 0.65). Almost one in five (19%) current smokers had carbon monoxide levels above 13 parts per million, compared to less than 2% of non-smokers or former smokers.

Professor Henry said: "Our study shows that carbon monoxide levels above 13ppm are associated with a worse prognosis when a smoker is admitted to hospital for an acute cardiac event. We also found that carbon monoxide levels were a much stronger predictor of adverse events than smoking status."

He concluded: "The results suggest that exhaled carbon monoxide could be measured in cardiac patients upon admission to better assess their prognosis. Carbon monoxide poisoning is treated with a high flow of oxygen that quickly reduces dangerous levels in the blood. This therapy could improve the post-heart attack outlook for smokers with carbon monoxide levels above 13 parts per million."

Source:

European Society of Cardiology

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