Pulmonary angiography in severe chronic pulmonary hypertension

Pulmonary angiography in a non-teaching hospital over a 12-year period

OBJECTIVE

To report the safety of pulmonary angiography in a non-teaching hospital and discuss the place of this investigation in the diagnosis of pulmonary embolism.

DESIGN AND SETTING

A retrospective review of all patients undergoing pulmonary angiography over a 12-year period, November 1979 to October 1991, at Dandenong Hospital, Melbourne. A protocol was established whereby each procedure was performed with the assistance of staff and equipment from the intensive care unit to provide haemodynamic monitoring and measurement of pulmonary artery pressures.

PATIENTS

During the review period 114 patients underwent pulmonary angiography, most (108) for suspected pulmonary embolism.

RESULTS

One hundred and fifteen pulmonary angiograms were performed, and no deaths related to the procedure occurred. Complications included perforation of the right atrium in three patients, with no sequelae. Cardiac arrhythmias were common but self-limiting.

CONCLUSION

In our series, pulmonary angiography was a safe procedure if undertaken with the appropriate monitoring measures. A protocol which includes the participation of the intensive care unit has proved helpful. In addition, it was found that clinical symptoms and signs were unreliable and in 24 patients who also had ventilation-perfusion (V/Q) scans, only seven scans were accurate. A review of the literature indicates that V/Q scans lack specificity and that pulmonary angiography may be performed safely. The latter investigation should be more frequently performed.

Pericardial adaptation in severe chronic pulmonary hypertension. An intraoperative transesophageal echocardiographic study

BACKGROUND

The pericardium both limits cardiac distension and accentuates ventricular interdependence. Although this effect appears minimal under normal circumstances, the pericardium markedly restricts acute cardiac enlargement. Animal studies have demonstrated gradual pericardial adaptation and expansion in chronic volume overload and cardiomegaly, but the pericardial response in humans with cardiac hypertrophy and enlargement has not been examined fully. To investigate this further, 14 patients with right ventricular hypertrophy and cardiomegaly secondary to chronic pulmonary thromboembolic disease and severe pulmonary hypertension were studied during pulmonary thromboendarterectomy.

METHODS AND RESULTS

Simultaneous intraoperative transesophageal Doppler echocardiography and direct biventricular hemodynamic measurements were performed at steady state immediately before and after pericardiotomy. All hemodynamic variables showed no significant change before and after pericardiotomy, including heart rate (76 +/- 16 versus 75 +/- 15 beats per minute), mean pulmonary arterial pressure (46.3 +/- 11.1 versus 45.5 +/- 11.7 mm Hg), cardiac index (1.8 +/- 0.5 versus 2.0 +/- 0.6 l/min/m2), left ventricular end-diastolic pressure (5.9 +/- 5.7 versus 7.1 +/- 5.0 mm Hg), and right ventricular end-diastolic pressure (7.9 +/- 6.6 versus 8.0 +/- 6.7 mm Hg). Similarly, there were no significant changes in all Doppler echocardiographic parameters, including right ventricular end-diastolic area (23.2 +/- 5.7 versus 22.6 +/- 5.4 cm2), left ventricular end-diastolic area (15.3 +/- 5.9 versus 15.5 +/- 4.4 cm2), the position of the interventricular septum, and the Doppler-derived mitral inflow measures of diastolic function.

CONCLUSIONS

The pericardium appears to have little influence on the marked cardiac and septal deformations seen in patients with chronic, severe right ventricular pressure overload and cardiomegaly. This study confirms that the human pericardium is capable of adapting over time to changes in cardiac size and geometry.

Paucity of angiographic findings despite extensive organized thrombus in chronic thromboembolic pulmonary hypertension

The authors describe a patient with chronic thromboembolic pulmonary hypertension. At pulmonary angiography, only severe hypertension with pruning of peripheral vessels was seen; the right pulmonary artery appeared normal. Despite the limited use of a nonionic contrast material, the patient died 11 hours after the study. At autopsy, a laminated well-organized thrombus that occupied virtually all of the right pulmonary artery and adhered to the vessel wall was seen. Other modalities should be investigated to help establish the diagnosis of chronic thromboembolic pulmonary hypertension.

Deep venous thrombosis and pulmonary embolism

All surgical patients are at risk for the development of deep venous thrombosis and subsequent pulmonary embolism or postphlebitic syndrome. The evolution of ultrasonographic imaging has increased the awareness of prevention, diagnosis, and treatment of deep venous thrombosis. Duplex imaging and Doppler color flow imaging have made the diagnosis of deep venous thrombosis relatively simple, painless, inexpensive, and definitive. These procedures have gained acceptance by both patients and physicians. Several risk factors have been identified that increase the chance of the development of deep venous thrombosis. These factors include a history of deep venous thrombosis, presence of a malignant process, increasing age, cigarette smoking, obesity, prolonged bed rest, and general anesthesia. The greater the number of risk factors, the more aggressive prophylaxis should be. Means of prophylaxis have improved, and surgeons now generally agree that some form of prophylaxis is required. Heparin and intermittent compression devices appear to be equally effective in preventing deep venous thrombosis. The addition of venous monitoring in high-risk patients permits immediate identification of the presence of deep venous thrombosis. During the last decade, the treatment of patients with deep venous thrombosis has changed little. Heparin followed by warfarin remains the treatment of choice. A small group of patients receive fibrinolytic therapy for deep venous thrombosis. Although the incidence of postoperative deep venous thrombosis has decreased during the last decade, it remains a significant complication.

Primary pulmonary hypertension

Primary pulmonary hypertension is a rare disease of unknown etiology, which mainly affects people in the third and fourth decades. Although the clinical cause is highly variable and spontaneous regression has been described, survival rates are usually poor, averaging only three years after diagnosis. Treatment with vasodilator agents, especially calcium channel blockers and prostaglandins, usually improves symptoms, but have not been shown to improve chances for survival. In a few selected patients who continue to deteriorate despite medical treatment, lung transplantation may be the only option for improving function and survival.

Catheter-based intravascular ultrasound imaging of chronic thromboembolic pulmonary disease

Pulmonary thromboendarterectomy is now the treatment of choice for pulmonary hypertension due to chronic pulmonary thromboemboli. A precise assessment of location and extension of these thrombi is important because only proximal chronic pulmonary thromboemboli are accessible to surgery. Because intravascular ultrasound imaging can assess not only arterial luminal size, but also wall thickness, its value as a complement to angiography was assessed in 11 patients aged 35 to 64 years with severe pulmonary hypertension (systolic pulmonary artery pressure, mean +/- standard deviation 70 +/- 19 mm Hg; pulmonary artery resistance, 609 +/- 297 dynes.s.cm-5). Intravascular ultrasound was obtained in 10 of 11 patients and no complication occurred. Intravascular ultrasound identified 10 segments with suspected chronic pulmonary thromboemboli in 7 patients, all confirmed at operation. Nine segments were considered normal, all of which (except 1) were free of chronic pulmonary thromboemboli at operation. Image quality was highly dependent on pulmonary artery size and position of the catheter. Therefore, intravascular ultrasound of pulmonary arteries is feasible and safe in patients with pulmonary hypertension. It may help to assess the location and extension of the pathologic process involving pulmonary arteries.

Pulmonary vascular steal in chronic thromboembolic pulmonary hypertension

After pulmonary thromboendarterectomy, performed for relief of chronic thromboembolic pulmonary hypertension, perfusion lung scans have frequently disclosed new perfusion defects in segments served by undissected pulmonary arteries. Our hypotheses were that these new postoperative defects occurred with great frequency and did not represent postoperative vessel occlusion. We retrospectively reviewed the preoperative and postoperative perfusion scans of 33 consecutive patients undergoing pulmonary thromboendarterectomy. New postoperative perfusion defects were noted in 23 of 33 patients. The incidence of new defects was increased tenfold in segments that had (1) normal preoperative angiographic findings, (2) normal preoperative radionuclide perfusion, and (3) not been entered at the time of surgery. Postoperative angiograms, available in 15 of 33 patients, documented the nonembolic, nonocclusive nature of the new perfusion scan defects. The most plausible alternate explanation for this previously undescribed finding is a redistribution of pulmonary arterial resistance induced by the thromboendarterectomy, namely, a pulmonary vascular "steal."

Influence of Doppler sample volume location on the assessment of changes in mitral inflow velocity profiles

Previous studies that have validated Doppler indexes of mitral inflow have used pulsed wave sample volume locations either at the level of the mitral valve anulus or at the tips of the mitral valve leaflets. Although significant differences between absolute values for peak velocities and velocity time integrals at these sample volume locations have previously been reported, no information exists that has compared changes in inflow profiles after an intervention to improve left ventricular filling. To address this question, 13 patients with severe pulmonary hypertension (mean pulmonary artery pressure, 50 +/- 13 mm Hg) caused by chronic thromboembolic disease were studied with use of Doppler echocardiography immediately before and after surgical reduction of pulmonary hypertension (pulmonary vascular resistance decreased from 916 +/- 413 to 233 +/- 89 dynes.sec.cm5). This clinical model has been shown to have abnormal mitral inflow velocity profiles that improve markedly after surgery. Doppler measures of early and late peak velocities were significantly lower both before and after surgery when sampling at the mitral anulus compared with the leaflet tips, although late filling parameters and the deceleration of early flow velocity tended to differ little. With surgery, the significant increase in peak early velocity and the ratio of early to late velocity was present regardless of the sample volume location (peak E at leaflet tips, 47.1 +/- 16.0 to 68.9 +/- 15.4 [p less than 0.001], and at anulus, 40.7 +/- 11.3 to 56.2 +/- 14.6 cm/sec [p less than 0.001]; peak E/A at leaflet tips, 0.95 +/- 0.4 to 1.55 +/- 0.9, and at anulus, 0.78 +/- 0.3 to 1.32 +/- 0.7 [both p less than 0.02]).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical correlates of angiographically diagnosed idiopathic pulmonary hypertension

During 1970-87 43 patients with unexplained pulmonary hypertension (mean pulmonary arterial pressure greater than 25 mm Hg) were admitted to the Brompton Hospital and classified by angiographic criteria as having either symmetrical peripheral pulmonary artery pruning (thought to represent primary plexogenic pulmonary arteriopathy), n = 21, or asymmetrical pulmonary arterial occlusions (thought to represent chronic thromboembolic disease), n = 22. Patients with symmetrical pulmonary arteriopathy had significantly higher mean pulmonary arterial pressures (67 mm Hg) at the time of presentation than those with asymmetrical pulmonary arteriopathy (49 mm Hg). Clinical distinction between these two groups was impossible. Survival from the time of diagnosis was similarly poor in the two groups (26 weeks and 38 weeks) and did not correlate with any of the haemodynamic measurements. The difficulties in making distinctions between these conditions are discussed.

Primary pulmonary hypertension in adults

Primary pulmonary hypertension is an enigmatic disease found predominantly in young women, but it also affects a significant number of middle-aged and elderly males and females. Its onset, characterized by progressively worsening dyspnea, fatigue, and chest pain, is insidious. Three distinct histopathologic subtypes have been identified, and the natural history of the disease process has been well-defined. Pharmacologic treatment options have, in general, been disappointing, and it appears that heart-lung transplantation will be applied only to a small minority of young patients with primary pulmonary hypertension in the near future. We review the histopathology, evaluation, treatment, and prognosis of primary pulmonary hypertension.

Primary pulmonary hypertension. Vascular structure, morphometry, and responsiveness to vasodilator agents

The use of pharmacologic agents in the treatment of pulmonary hypertension has not proved to be uniformly successful or predictable. One possible reason for the vagaries in response is that the pulmonary vascular lesions are not consistent. We examined the relation between the structure of the pulmonary resistance vessels in unexplained (primary) pulmonary hypertension and the response to pulmonary vasodilators. Our study involved 19 patients with clinically unexplained pulmonary hypertension (mean pressure, 59 +/- 14 mm Hg). After characterizing them clinically and performing control hemodynamic measurements, we determined the acute effects of a series of vasodilator agents that have different mechanisms of action. In 16 patients, lung biopsy material was related to the hemodynamic studies; in nine patients, including six who had undergone open lung biopsy, the hemodynamic studies were related to the pathologic changes found at autopsy. Histologic specimens from all 19 patients were evaluated qualitatively and sorted into three subsets of hypertensive pulmonary arteriopathy: medial hypertrophy (with minimal intimal proliferation), arteriopathy with plexiform lesions (associated predominantly with concentric laminar intimal proliferation and fibrosis), and arteriopathy with microthrombotic lesions (associated predominantly with eccentric intimal proliferation and fibrosis). The 16 lung biopsies were also quantitated by morphometric techniques. Using a decrease in calculated pulmonary vascular resistance of more than 30% accompanied by a decrease in mean pulmonary arterial pressure of at least 10% to define vasodilation, only four patients were responders. The patients varied considerably in their responses to different vasodilator agents. Patients with similar clinical and hemodynamic profiles differed considerably with respect to the nature of their pulmonary vascular obstructive lesions and their responses to vasodilator agents. Qualitative histologic examination of lung tissue did not provide a basis for predicting how individual patients would respond to vasodilator agents. However, quantitative morphologic analysis of the initial open lung biopsy specimens did prove helpful in predicting acute responsiveness to vasodilator agents and the subsequent clinical course of these patients with unexplained (primary) pulmonary hypertension. An intimal area of more than 18% of the vascular cross-sectional area had an 85% predictive value for identifying the patients who did poorly during the first 36 months of follow-up.

Early improvement in left ventricular diastolic function after relief of chronic right ventricular pressure overload

Chronic right ventricular pressure overload is associated with left ventricular diastolic dysfunction. Whether or not an abrupt reduction in pulmonary artery pressure in patients with chronic pulmonary hypertension results in early improvement of left ventricular diastolic function is unknown. To assess this, the Doppler indexes of left ventricular diastolic function and echocardiographic measures of left ventricular volume were analyzed in 22 patients (age, 41 +/- 14 years, mean +/- SD) before and within 1 week after pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension. Mean duration of cardiopulmonary symptoms was 37 months (range, 4 months to 9 years). After operation, mean pulmonary artery pressure and pulmonary vascular resistance decreased (50 +/- 13 to 29 +/- 9 mm Hg and 904 +/- 654 to 283 +/- 243 dynes.sec/cm5, respectively, both p less than 0.001), pulmonary artery wedge pressure was unchanged (11 +/- 5 to 12 +/- 5 mm Hg), and cardiac index increased (2.0 +/- 0.5 to 2.8 +/- 0.7 l/min/m2 p less than 0.001). Left ventricular end-diastolic volume and stroke volume increased significantly (58.5 +/- 18.0 to 76.6 +/- 25.0 ml and 30.3 +/- 12.3 to 41.8 +/- 12.5 ml, respectively, both p less than 0.001) after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic cor pulmonale

Chronic cor pulmonale is defined as right heart hypertrophy and/or chronic right heart failure. There are many etiologies, but the common cause is increased right heart work from pulmonary hypertension. Etiology can be conveniently discussed by assuming two prototypes, the asphyxial or hypoxic type and the vascular obliterative type. A common cause of the asphyxial type is chronic obstructive pulmonary disease, and the obliterative type is represented by chronic pulmonary thromboembolic disease or primary pulmonary hypertension. Pathology is discussed, emphasizing the cardiac manifestations of chronic cor pulmonale including data of specific cardiac chamber size. An overview of hemodynamics is given, and the use and limitation of electrocardiography and chest x-rays are discussed. The exciting potential use of echocardiography for the serial non-invasive measurement of anatomical and pathophysiological features is outlined, along with the value of a careful physical examination and the proper utilization of laboratory tests in the diagnosis of chronic cor pulmonale. In the patient with the asphyxial type, the treatment of pulmonary infectious exacerbations, the role of corticosteroids, digoxin, diuretics, phlebotomy, bronchodilators (theophylline, beta adrenergic agonists, and anticholinergics), and long-term oxygen therapy is noted. The controversy surrounding the use of vasodilators and calcium blockers in these patients is discussed. Treatment aspects of the vascular obliterative type, including the role of vasodilators, calcium blockers, prostacyclin, anticoagulants, and overall strategy are discussed. A brief note is mentioned of the promising role of surgical therapy in chronic thromboembolic disease causing chronic cor pulmonale.

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is equated with chronic bronchitis and emphysema as one disease entity. In COPD airflow limitation is relatively persistent--unlike asthma. Tests for "small-airways disease" form no part of routine practice, for their accuracy in detecting pathological change is debatable. The proteolytic theory of the pathogenesis of emphysema highlights the role of neutrophil elastase, antielastases, oxidants, antioxidants, and thus of potential new treatments. Clinical features of COPD include breathlessness, cough, and sputum, with airflow obstruction and lung hyperinflation. The differential diagnosis includes bronchiectasis, cystic fibrosis, and pulmonary hypertension, but pulmonary fibrosis, etc., is distinguished by radiological infiltrates. Plain chest radiography cannot reliably diagnose emphysema in life, but a new method measuring lung density from the computed tomographic (CT) scan allows location, quantitation, and diagnosis of emphysema (defined by enlargement of distal air spaces) in humans in life. "Pink puffers" with breathlessness, hyperinflation, mild hypoxemia, and a low PCO2 are contrasted with "blue bloaters" with hypoxemia, secondary polycythemia, CO2 retention, and pulmonary hypertension and cor pulmonale. Antismoking measures are a major aim in management. A bronchodilator regimen combining a slow-release oral theophylline with an inhaled beta 2-agonist, ipratropium, and high-dose inhaled steroids is proposed because even modest improvement in obstruction can help these patients. In acute exacerbations with purulent sputum, antimicrobials against Streptococcus pneumoniae and Hemophilus influenzae are used with controlled oxygen therapy aiming to keep the arterial PO2 over 50 mm Hg without the pH falling below 7.25. Influenza prophylaxis is recommended, but pneumococcal vaccination remains debatable. Chronic under-nutrition in "emphysema" implies controlled trials of feeding regimens--but these remain to be assessed. Long-term oxygen therapy is the only treatment known to prolong life in blue bloaters, and oxygen concentrators and transtracheal oxygen delivery are discussed. Pulmonary vasodilators (e.g., beta 2-agonists, hydralazine, nifedipine, angiotensin-converting enzyme [ACE] inhibitors, etc.) have not yet been proved to provide long-term reduction in pulmonary arterial pressure. Blue bloaters have severe nocturnal hypoxemia in rapid eye movement (REM) sleep that is corrected by oxygen or the investigational drug almitrine.(ABSTRACT TRUNCATED AT 400 WORDS)

Doppler assessment of changes in right-sided cardiac hemodynamics after pulmonary thromboendarterectomy

It is not known whether Doppler echocardiography can accurately follow changes in right-sided cardiac hemodynamics after a therapeutic intervention in patients with pulmonary artery (PA) hypertension. Therefore, Doppler measurements of the maximal velocity of the tricuspid regurgitant jet and the acceleration time of the PA velocity profile were obtained in 28 patients before and after pulmonary thromboendarterectomy for chronic thromboembolic PA hypertension. Doppler values were compared with hemodynamic variables obtained at cardiac catheterization. Postoperatively, decreases in mean PA pressure (50 +/- 14 to 28 +/- 8 mm Hg), transtricuspid systolic pressure difference (69 +/- 21 to 36 +/- 14 mm Hg) and Doppler measurement of the maximal velocity of the tricuspid regurgitant jet (4.1 +/- 0.7 to 2.7 +/- 0.5 m/s) were noted, while acceleration time increased (57 +/- 16 to 94 +/- 18 ms, all p less than 0.001) compared with preoperative values. For the population as a whole, the calculated systolic transtricuspid pressure difference determined from the maximal velocity of tricuspid regurgitation correlated well with the catheterization systolic transtricuspid pressure difference (r = 0.93, p less than 0.001) and the acceleration time correlated with mean PA pressure (r = -0.81, p less than 0.001). More importantly, the change in the maximal velocity of tricuspid regurgitation for postoperative patients was found to correlate with the change in catheterization systolic transtricuspid pressure difference (r = 0.82, p less than 0.001), while the change in acceleration time correlated weakly with the change in mean PA pressure (r = -0.41, p = 0.053).(ABSTRACT TRUNCATED AT 250 WORDS)

Early changes of right heart geometry after pulmonary thromboendarterectomy

To determine the changes in right heart hemodynamics and geometry early after surgery for chronic pulmonary hypertension due to large vessel thromboembolic occlusion, 30 patients were evaluated 8 +/- 8 days (mean +/- SD) before and 6 +/- 4 days after pulmonary thromboendarterectomy by two-dimensional echocardiography and right heart catheterization. Surgery resulted in an early significant improvement in hemodynamic variables including mean pulmonary artery pressure (48 +/- 12 to 28 +/- 8 mm Hg, p less than 0.001), right ventricular systolic pressure (76 +/- 20 to 47 +/- 15 mm Hg, p less than 0.001), pulmonary vascular resistance (935 +/- 620 to 278 +/- 252 dynes.s.cm-5, p less than 0.001) and cardiac index (2.0 +/- 0.5 to 2.9 +/- 0.6 liters/min per m2, p less than 0.001). Similarly, echocardiographic variables of right heart structures, which were well outside the normal range preoperatively, improved significantly early after thromboendarterectomy. These included diameters of the pulmonary artery (2.8 +/- 0.3 to 2.4 +/- 0.4 cm, p less than 0.001), inferior vena cava (2.9 +/- 0.6 to 2.2 +/- 0.4 cm, p less than 0.001) and right atrium (6.8 +/- 1.5 to 5.9 +/- 1.5 cm, p less than 0.001) as well as right ventricular short axis (4.5 +/- 0.8 to 3.7 +/- 0.8 cm, p less than 0.001) and long axis (8.7 +/- 0.9 to 8.1 +/- 0.9 cm, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)