Previous Pulmonary Embolism Research Articles

Incidence of Pulmonary Embolism After Total Knee Arthroplasty With Low-Dose Coumadin Prophylaxis

The incidence of pulmonary embolism (PE) in osteoarthritic patients prophylaxed with low-dose coumadin after cemented total knee arthroplasty (TKA) was investigated prospectively. Each patient had a preoperative perfusion scan and a ventilation-perfusion scan on the seventh postoperative day. Pulmonary embolism was diagnosed by a high probability ventilation-perfusion scan or positive arteriogram. Patients with a moderate probability scan had an arteriogram to rule out PE. Pulmonary embolus was identified in 48 (5.6%) of 852 TKAs in 755 patients. Of these, six (0.7%) were symptomatic, and no fatal PE was identified. Age, gender, and weight did not show statistical differences comparing the PE and non-PE groups, nor did the incidences of previous PE, contralateral phlebitis, malignancy, and diabetes. A history of ipsilateral phlebitis increased the risk of PE from 5.2% to 13%, and a history of cardiac disease decreased the risk from 7.8% to 4.2%. Type of anesthesia, blood loss, tourniquet time, and prosthesis type were not significant factors. With the exception of previous contralateral phlebitis, traditional risk factors for PE were not found to increase risk of PE with low-dose coumadin prophylaxis. Spinal anesthesia that has been shown to be protective in total hip surgery was not a significant factor in this study.

Frequency of pulmonary embolism in ambulant patients with pelvic vein thrombosis: A prospective study

One hundred thirty-nine consecutive patients (average age 70.1 years) who were able to walk with a swollen leg were seen at the clinic where diagnosis of acute deep vein thrombosis (DVT) extending to the pelvis was confirmed by injecting microspheres labeled with technetium 99m into the dorsal foot vein (radionuclide venography). Thirty-nine (28%) of these patients had malignant disease. Perfusion lung scans performed immediately after radionuclide venography were supplemented by inhalation scans (99mTc-labeled diethylenetriamine pentaacetic acid aerosol) in case of perfusion defects. During scintigraphy patterns highly indicative of pulmonary embolism (PE) were found in 80 patients (58%), but only 11 (7.9%) had minor clinical symptoms. All patients were admitted to the ward, were given standard heparin subcutaneously (35,000 to 40,000 units/24 hr) and firm bandages, and were encouraged to walk. After 11 days pulmonary scintigraphy was repeated and revealed no change in 55 of 59 patients without PE and in 40 of 80 patients with PE. Thirty-three patients (23.7%) showed regression of perfusion defects. New PE developed in 11 patients (7.9%, four without and seven with previous PE). Autopsy revealed that one 80-year-old patient with prostatic carcinoma had died of massive PE. When comparing this frequency of newly developed PE during ambulation with the occurrence of PE after bed rest, according to the literature, it is no more dangerous for a mobile patient with proximal DVT to walk wearing a firm bandage than it is for the patient to be in bed. Therefore we recommend treating mobile patients with DVT by use of anticoagulation and firm compression bandages and without immobilization.

Chronic unilateral hyperlucent lung. A consecutive series of 40 patients.

A clinical series of 40 consecutive patients with chronic unilateral hyperlucent lung was analysed. Swyer-James (MacLeod) syndrome turned out to be the most common diagnosis (18 patients, 45%). Other causes were localized emphysema (8 patients, 20%), congenital hypoplastic pulmonary artery (4 patients, 10%), previous massive pulmonary embolism (4 patients, 10%), bronchial carcinoma (3 patients, 7.5%), sequelae of radiation therapy (2 patients, 5%) and benign intrabronchial neoplasm (1 patient, 2.5%). The reduction of pulmonary vasculature was scored (0-9). The most extensive reduction was found in patients with Swyer-James syndrome (mean 5.8), whereas patients with bronchial cancer had the smallest changes (mean 3.0).

Risk Factor Assessment in 101 Total Hip Arthroplasties

Our experience with 101 consecutive T.H.A.'s in 91 patients was examined in an attempt to identify preoperative risk factors for postoperative medical complications, especially pulmonary embolism and thrombophlebitis. Six per cent of patients developed postoperative clinical thrombophlebitis, and 8% a pulmonary embolism. Advancing age and previous venous thrombosis served as predictors for pulmonary embolism and thrombophlebitis, respectively (p less than 0.01), but obesity, venous varicosities, diabetes mellitus, cigarette smoking, previous pulmonary embolism, and length of surgery did not, for either. Fifty per cent of the patients with preoperative abnormal kidney function developed some form of medical complication postoperatively, a significant increase in risk (p less than 0.05) over patients with normal kidney function. We were unable to identify an increase in postoperative atelectasis or pneumonia associated with smoking or obesity in these patients. No consistent decrease in post-operative medical morbidity could be assigned to preoperative medical consultations, suggesting that we have not yet identified all significant risk factors. A thorough preoperative preparation and improvement in intra- and postoperative techniques and management may account for differences found in this study from traditionally held risk factors.

Risk Assessment of Pulmonary Embolism by Multivariate Analysis

A prospective study of 6,527 hospitalized patients was performed to evaluate the effectiveness of multivariate analysis of risk factors to correctly designate risk for pulmonary embolism. History of previous pulmonary embolism was the single most important factor. In patients without prior history, five factors emerged: inactivity, congestive heart failure, Doppler ultrasound evidence of deep-vein occlusion, female sex, and black race. Used together, these factors permitted a discrimination of risk such that 68.7% of pulmonary embolization was found to occur in 32.2% of the population designated as showing increased risk. Multivariate analysis of clinical factors improved assessment of risk, compared to the use of lower extremity findings alone, and proved to be useful in identifying individuals at increased risk for pulmonary embolism.

Prevention of venous thromboembolism in surgical patients.

DESPITE recent advances in diagnosis, venous thrombosis and pulmonary embolism remain major problems in surgical patients. Evidence of previous pulmonary embolism can be found in more than 60 per cent of routine autopsies.1 Pulmonary embolism is a frequent postoperative complication in general surgical, orthopedic and gynecologic patients and is the most common cause of death in the elderly injured.2 Elevations in the concentration of plasma procoagulants, increased fibrinogen levels, thrombocytosis, increased platelet reactivity and defective fibrinolysis are commonly observed after major surgery.3 Augmented by venous stasis engendered by recumbency or immobilization in a chair, these abnormalities seriously predispose to postoperative . . .

Deep vein thrombosis of the leg: Is there a “high risk” group?

Two hundred and three patients undergoing elective surgery were investigated to determine the group of patients who are at a “great risk” of developing deep vein thrombosis. It was found that the patients who formed this group included those who had a history of previous deep vein thrombosis or pulmonary embolism, those who had varicose veins or underwent operation for malignant disease, and elderly patients (over sixty-one years) having major operations. All of these patients are at a “great risk” of developing thrombosis during the postoperative period. Two hundred and three patients undergoing elective surgery were investigated to determine the group of patients who are at a “great risk” of developing deep vein thrombosis. It was found that the patients who formed this group included those who had a history of previous deep vein thrombosis or pulmonary embolism, those who had varicose veins or underwent operation for malignant disease, and elderly patients (over sixty-one years) having major operations. All of these patients are at a “great risk” of developing thrombosis during the postoperative period.

Clinical and physiologic studies in pulmonary thromboembolism ∗

The clinical and physiologic studies of 72 patients with pulmonary thromboembolism were analyzed in detail. Pulmonary emboli occurred most frequently in the setting of some chronic condition, such as heart disease, previous pulmonary embolism, or chronic obstructive pulmonary disease. Coronary disease was most common, followed by mitral disease. The incidence of chronic bronchitis and emphysema can be expected to rise. The four most often encountered symptoms were: dyspnea in all patients, cough and pleural pain in about two thirds, and hemoptysis in slightly more than one third. Nonspecific physical findings were most frequent: loud P 2, tachypnea, rales and tachycardia. More specific findings of embolism, such as pleural friction rub and chest splinting, occurred in less than a fifth of the patients. Phlebitis was present in only a third. No specific laboratory test is presently available, but determination of enzyme levels (LDH, SGOT) were useful in suggesting the presence of pulmonary embolism. Over half of the patients had the characteristic elevated level of serum lactic dehydrogenase (LDH) and a normal level of serum glutamic oxalacetic transaminase (SGOT). However, negative studies do not exclude embolism. The most frequent biochemical triad consisted of elevated LDH and normal SGOT and bilirubin. Bilirubin elevation generally signaled the presence of complicating congestive failure. The white cell count in uncomplicated embolism was less than 15,000/mm. 3 Ventilatory derangements included hyperventilation, pulmonary restriction, bronchoconstriction and diminished diffusing capacity. Impairment of oxygenation was observed in almost all patients. Two thirds showed evidence of venous admixture, and other contributing factors responsible for hypoxemia were diffusion defects and diminished ventilation-perfusion ratios. Virtually all patients with pO 2 levels less than 60 mm. Hg showed evidence of venous admixture. Pulmonary hypertension was observed in varying degrees in 80 per cent of the patients. Almost all patients with mean pulmonary artery pressures above 30 mm. Hg and all those with pressures above 40 had hemodynamic evidence of right heart failure. About two-thirds of the patients showed a diminished cardiac index, increased arteriovenous oxygen extraction, and elevated right ventricular end-diastolic pressure when these combined determinations were made. Fifty-eight per cent of the patients were initially correctly diagnosed. The others had various nonspecific symptoms and signs attributed to congestive failure, pneumonia, myocardial infarction or chronic pulmonary disease. In each instance, a diagnostic protocol was useful in heightening suspicion of pulmonary emboli. The final decision was based on the results of lung scanning, selective pulmonary angiography, or both.

The implications of patterns of occlusion in arteriosclerosis

W ith the advent of operative approaches to the arteries came the necessity for an exact localization of the lesions of arteriosclerosis. So far, more of such data are available for the lower extremities than for other parts of the body. As more information is gained, it becomes apparent that certain patterns of the arterial involvement may be expected in certain clinical situations. As examples, I may cite the youth of patients with occlusion commencing in the aortic bifurcation, the tendency for diffuse arterial involvement in diabetes, and the association of pulmonary arteriosclerosis with previous pulmonary embolism for hypertension. These associations strongly suggest that arteriosclerosis is not a disease per se, but rather the end result of a variety of causative disease states. There are additional indications that some sites of initial involvement are associated with relative discreteness of disease, others with diffuseness. This, in turn, carries an implication of varying prognosis, since diffuse disease involves many areas in the body, and also shows a tendency to a more rapid progression of disease. I will attetipt in this paper to review what is known of the locations of arteriosclerosis, with some consideration of the means of recognizing the lesions in these places, and I will mention the varying prognoses which attach to different sites of involvement. Anatomic factors in the efects of occlusion. Peculiarities in the anatomic pattern of the arteries, particularly with respect to their anastomotic connections, are important in varying the effects of occlusion from one site to another, and between individuals as well. Ischemia of a limb often fails to follow a glove or stocking distribution because of a relative circumscription that exists for the blood supply to muscle, nerve, and even to portions of the integument.ga For this reason, ischemia may be limited to parts of an extremity, as may be seen in interruption to the vessels of a viscus in the abdominal cavity. Thus, because of occlusion of the hypogastric artery, claudication often persists in the buttock after successful restoration of flow to the rest of the limb. Similarly, a neuritis or a cutaneous infarct may be due to an occlusion of the nutrient artery to those parts quite out of proportion to the vascular status of the limb as a whole. Unexpectedly severe ischemia may occur in organs with multiple sources of supply if the anastomoses between these sources are imperfect. -A detailed consideration