DIFFERENTIATING PPH FROM PULMONARY THROMBOEMBOLISM

A new method can help differentiate chronic pulmonary thromboembolism (CPTE) from primary pulmonary hypertension (PPH). By measuring the reflection of waves in the pulmonary vasculature, physicians can determine whether the underlying abnormality affects predominantly the proximal arteries (suggesting CPTE) or the peripheral arteries (indicating PPH).

Nakayama et al observed 62 consecutive patients at the National Cardiovascular Center in Osaka, Japan, all of whom had been admitted between January 1997 and May 2000 for symptomatic pulmonary hypertension.

Pulmonary arterial pressure was measured using a balloon-tipped, flow-directed catheter. CPTE was diagnosed in 31 patients with appropriate clinical histories through pulmonary angiography and radioisotope ventilation-perfusion imaging. Diagnosis of PPH in the remaining patients was made after exclusion of such secondary pulmonary hypertension causes as mitral valve diseases, congenital heart diseases, left ventricular failure, and CPTE.

The researchers found between-group differences in two markers of pulmonary arterial reflection: the augmentation index (the ratio of inflection pressure to pulse pressure) and inflection time (the interval between the onset of the systolic pressure waveform and the inflection point). Mean augmentation index measurements in the CPTE and PPH patients were 27.4% and –25.1%, respectively.

The mean inflection time in those two groups was 97 ms and 210 ms, respectively. Using a cutoff point of 12%, the sensitivity and specificity of the augmentation index were each 94% for differentiating CPTE from PPH. The corresponding figures for an inflection time cutoff point of 122 ms were 93% and 97%.

The researchers therefore concluded that pulmonary arterial reflection was useful in differentiating CPTE and PPH.

Nakayama Y, Nakanishi N, Hayashi T, et al. Pulmonary artery reflection for differentially diagnosing primary pulmonary hypertension and chronic pulmonary thromboembolism. J Am Coll Cardiol. 2001;38:214-218.

ABCIXIMAB DOES NOT INCREASE STROKE RISK

The risk for stroke faced by patients who receive abciximab while undergoing percutaneous coronary intervention (PCI) is no greater than the risk faced by PCI patients given placebo.

Akkerhuis et al evaluated data from four double-blind, placebo-controlled, randomized trials that included 8,555 patients. These studies took place in 257 American and European hospitals between November 1991 and October 1997.

Patients were divided into groups receiv ing a bolus and an infusion of the platelet glycoprotein IIb/IIIa receptor inhibitor (n = 5,476) or placebo (n = 3,079). Stent deployment may or may not have been involved in any of the procedures.

The main outcome measure evaluated was risk of hemorrhagic or non-hemorrhagic stroke within 30 days of treatment; 33 such strokes occurred in 31 patients. No significant difference in the rate of stroke was found between the abciximab and placebo groups; 0.4% of the patients given abciximab suffered strokes, compared with 0.29% of patients receiving placebo. Non-hemorrhagic and hemorrhagic strokes in the abciximab group occurred at rates of 0.24% and 0.16%, respectively; the placebo group experienced those events at rates of 0.20% and 0.10%, respectively.

In three of the four studies, some patients received standard-dose heparin along with abciximab; the rate of hemorrhagic stroke in these patients was 0.27%. Two of the studies also included low-dose heparin regimens; the hemorrhagic stroke rate was only 0.04% when low-dose heparin was administered. Because of the small numbers of patients involved, however, this difference did not reach statistical significance.

The conclusion drawn by researchers was that using abciximab in conjunction with heparin does not increase stroke risk in PCI patients; heparin, they said, should be administered in low, weight-adjusted doses.

Akkerhuis KM, Deckers JW, Lincoff AM, et al. Risk of stroke associated with abciximab among patients undergoing percutaneous coronary intervention. JAMA. 2001;286:78-82.

ANTIBIOTIC ROTATION HELPS PREVENT RESISTANCE

Quarterly rotation of empirical antibiotics may be an effective way to combat morbidity and mortality from antibiotic-resistant infections in intensive care units (ICUs), suggest Raymond et al.

Their prospective cohort study evaluated antibiotic rotation as a method for reducing the emergence of resistant organisms and thereby improving survival in 540 cases of infection identified during a two-year period in the University of Virginia Health Sciences Center’s ICU.

During the first year of the study, empiric antibiotics were administered according to the physicians’ prescriptions; during the second year, a quarterly rotating empiric antibiotic schedule was used.

The patients studied were taken from 1,456 consecutive admissions to the ICU; all had pneumonia, peritonitis, or sepsis of unknown origin.

Between the two years of study, no differences were noted in the patients’ mean APACHE II score, age, overall need for antibiotics, or duration of therapy. However, antibiotic rotation was associated with a marked decrease in the rate of resistant gram-positive coccal and gram-negative bacillary infections. For example, there were 7.8 resistant gram-positive coccal infections per 100 admissions among the patients treated with the rotated antibiotics, compared with 14.6 such infections per 100 admissions in the other group.

Resistant gram-negative bacillary infections occurred in 2.5 and 7.7 per 100 patients, respectively. Mortality related to infection was also reduced; there were 2.9 deaths per 100 admissions in the patients given rotated antibiotics, compared to 9.6 deaths per 100 admissions in the other group.

The researchers concluded that although further research was needed to determine the long-term efficacy of antibiotic rotation, it was clear in this case that it reduced infection and related mortality without increasing medication costs.

Raymond DP, Pelletier SJ, Crabtree TD, et al. Impact of a rotating empiric antibiotic schedule on infectious mortality in an intensive care unit. Crit Care Med. 2001;29:1101-1108.

LUNG FUNCTION MEASUREMENT ESTABLISHES TRANSPLANT TIMETABLE

Are patients with idiopathic pulmonary fibrosis (IPF) being referred too late for lung transplantation? To address this question, Mogulkoc et al evaluated the usefulness of pulmonary function tests (PFT) and high-resolution computed tomography (HRCT) in predicting survival in patients with usual interstitial pneumonia (UIP). The aim was to understand whether PFT results could improve referral timing for these patients.

The authors evaluated 115 patients with UIP, all of whom were younger than age 65 (median age, 56). Diagnosis of UIP-pattern IPF was achieved through surgical lung biopsy in 38% and on the basis of HRCT appearance in the remaining 62%. Median follow-up was 26 months; 46 (40%) of patients died during that time.

Two PFT results were found to discriminate between survivors and non-survivors: a diffusing capacity of the lungs for carbon monoxide (DlCO) as a percentage of predicted of 39% and an HRCT-fibrosis score of 2.25.

The researchers concluded that a combination of DlCO and the HRCT-fibrosis score produced the most accurate predictive data for IP patients younger than 65 years. Although they believed that the decision to refer a patient for transplantation should be based on the individual’s overall medical and psychosocial condition, this information could be useful in establishing a timetable by which such referrals could be made.

Mogulkoc N, Brutsche MH, Bishop PW, et al. Pulmonary function in idiopathic pulmonary fibrosis and referral for lung transplantation. Am J Resp Crit Care Med. 2001;164:103-108.

EN BLOC CHEST WALL RESECTION FOR NON–SMALL CELL CARCINOMA

A recent study objectively evaluated outcomes and concluded that en bloc chest wall resection is superior to extrapleural resection for treating non–small cell lung cancer (NSCLC). Facciolo et al consider their results in studying cancer that has invaded the chest wall to be strong, enough so that a surgeon’s experience may no longer be the sole criterion in deciding which procedure to use.

Between January 1990 and June 1999, 104 patients underwent en bloc resection with radical mediastinal lymphadenectomy. All procedures were performed by the same surgeon; there was no operative mortality. According to the researchers, the complication rate of 19% was similar to that experienced in the other 1,751 major pulmonary resections performed at their institution during this period.

Facciolo et al also noted that although en bloc resection might seem extreme, they were able to obtain microscopically disease-free margins, which had not been achieved through the extrapleural procedures performed at their facility.

The completeness of en bloc resection’s tumor removal produced favorable survival rates. Follow-up in 96 patients produced evidence of only one local recurrence. The overall, five-year survival rate was 61%, which Facciolo et al contrasted with studies producing three-year survival rates of 4% and 0% in patients undergoing incomplete, R1/R2 resection and no resection at all, respectively.

The researchers concluded that en bloc resection’s superior survival rates were due to its more complete removal of tumor from various tissues and that it was therefore superior to extrapleural resection.

Facciolo F, Cardillo G, Lopergolo M, et al. Chest wall invasion in non–small cell lung carcinoma: a rationale for en bloc resection. J Thorac Cardiovasc Surg. 2001;121:649-656.

ANNUAL REHAB FOR CHRONIC AIRWAY OBSTRUCTION?

Should patients with chronic airway obstruction (CAO) undergo pulmonary rehabilitation each year? New evidence suggests that annual rehabilitation does reduce the rate of exacerbations and provides short-term improvement in dyspnea, exercise tolerance, and health-related quality of life. However, it does not lower the annual number of CAO hospitalizations, and the short-term improvements do not result in long-term gains.

Foglio et al observed 61 CAO patients who underwent an eight-week outpatient pulmonary rehabilitation program (PRP1). These patients were randomized into two groups, the first of which (group 1) completed a second rehabilitation program (PRP2) one year later, whereas group 2 received no such therapy. At the end of the second year, both groups were reevaluated before beginning a third rehabilitation program.

Groups 1 and 2 were similar in baseline characteristics, and both their lung function test results and clinical course were similar in the year after PRP1. Immediately after PRP2, exercise tolerance, dyspnea, and health-related quality of life improved further in group 1; group 2 experienced no such improvement. By the end of the second year, though, the only difference between the two groups was that the rate of exacerbations was lower in group 1.

In both groups, the rate of hospitalizations was lower in the two years after PRP1 than it had been in the two years before the first rehabilitation program. And at the two-year follow-up, both groups continued to rate their health-related quality of life as higher than it had been before PRP1.

Foglio K, Bianchi L, Ambrosino N. Is it really useful to repeat outpatient pulmonary rehabilitation programs in patients with chronic airway obstruction? A two-year controlled study. Chest. 2001;119:1696-1704.

ASTHMA’S CONNECTION WITH IRRITABLE BOWEL SYNDROME

Irritable bowel syndrome (IBS) patients may have an increased prevalence of asthma, according to some research. This observation led investigators from Turkey to evaluate respiratory function in 133 IBS patients and 137 controls.

The two groups of patients were well matched; roughly 80% of both groups were women, and the average age in each group was about 40 years. Both groups completed subjective reports of respiratory symptoms, as well as pulmonary function tests.

Excluded from the study were persons older than 50 years, those with acute respiratory tract infection or gastrointestinal disease, current or former smokers, and those using medication that affects the autonomic nervous system.

Results revealed that 33.8% of the IBS patients had respiratory symptoms, compared with 5.8% of the controls. Further, 15.8% of the IBS patients, but only 1.5% of the controls, had a diagnosis of asthma.

There were also statistically significant differences between the two groups in forced expiratory volume in one second, maximal mid-expiratory flow, peak expiratory flow rate, and flow after 50% of vital capacity had been exhaled. The authors believe that their findings support the hypothesis that asthma and IBS may share common pathophysiologic mechanisms.

Yazar A, Atis S, Konca K, et al. Respiratory symptoms and pulmonary functional changes in patients with irritable bowel syndrome. Am J Gastroenterol. 2001;96:1511-1516.

DOES SMOKING CESSATION CAUSE RECURRENT DEPRESSION?

Smokers with a history of major depression who stop smoking are at high risk for recurrent depression, and this risk persists for at least six months after they quit. Antidepressant administration does not increase the likelihood that such patients can stop smoking, but it may lower their risk of recurrent depression.

Glassman et al enrolled 100 people who smoked one or more packs of cigarettes per day into a two-month smoking cessation trial. All participants had a history of major depression, but none had received an antidepressant medication for at least six months before the study’s start. Participants were randomized to receive the antidepressant sertraline or placebo, and were told to stop smoking 21 days after the start of treatment. They were then evaluated three and six months after treatment was completed.

Of the 76 participants who returned for follow-up, 42 were able to quit; 34 continued to smoke. Depression recurred in 13 of the abstainers and two of the smokers. The risk of recurrence was not time-dependent: Among the abstainers, seven episodes of recurrent depression occurred in the first three months of follow-up and six in the second three months.

The quit rate in the patients given sertraline was no different from that in patients given placebo. However, recurrent depression was twice as common in the placebo group. The authors concluded that patients with a history of major depression are at high risk of recurrence when they quit smoking. But it is not yet clear, they said, whether antidepressant administration or nicotine replacement is a reasonable prophylactic strategy.

Glassman AH, Covey LS, Stetner F, Rivelli S. Smoking cessation and the course of major depression: a follow-up study. Lancet. 2001;357:1929-1932.

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