David Poch

What are the important risk factors for healthcare-associated pneumonia?

Healthcare-associated pneumonia (HCAP) is a category of nosocomial pneumonia defined by the 2005 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines to include any patient who has been hospitalized in an acute care hospital for 2 or more days within the past 90 days; residents of a nursing home or long-term care facility; recipients of recent intravenous antibiotic therapy, chemotherapy, or wound care within the past 30 days; or patients who have attended a hospital or hemodialysis clinic. In creating this relatively new category the ATS/IDSA acknowledged that these patients are at increased risk for infection with antibiotic-resistant organisms and that initial inadequate antibiotic coverage leads to increased mortality. Risk factors for the development of pneumonia and the development of pneumonia caused by drug-resistant pathogens, primarily methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, are not the same among the subgroups of HCAP (i.e., dialysis patients have different risks than nursing home patients). Furthermore there is significant heterogeneity of risk factors for HCAP within the subgroups due to variations in contextual factors such as local microbiology and methods of health care delivery and variations of individual risk factors such as functional status or prior antibiotic exposure. This review examines the evidence for the creation of the category of HCAP, including the risk factors for drug-resistant pneumonia in each of the subgroups that constitute HCAP. This review demonstrates that the guidelines have effectively targeted a population at greater risk for pneumonia caused by drug-resistant pathogens. However, within the broad range of HCAP infections, there is significant heterogeneity in terms of the magnitude of the risk as well as the type of risk (i.e., risk for MRSA, multidrug-resistant gram-negative bacilli (MDR-GNB), or both).

Safety and efficacy of transition from systemic prostanoids to inhaled treprostinil in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a disease characterized by increased pulmonary pressures and chronic right heart failure. Therapies for moderate and severe PAH include subcutaneous (SQ) and intravenous (IV) prostanoids that improve symptoms and quality of life. However, treatment compliance can be limited by severe side effects and complications related to methods of drug administration. Inhaled prostanoids, which offer the advantage of direct delivery of the drug to the pulmonary circulation without need for invasive approaches, may serve as an alternative for patients unable to tolerate SQ/IV therapy. In this retrospective cohort study we collected clinical, hemodynamic, and functional data from 18 clinically stable patients with World Health Organization group I PAH seen in 6 large national PAH centers before and after transitioning to inhaled treprostinil from IV/SQ prostanoids. Before transition 15 patients had been receiving IV or SQ treprostinil (mean dose 73 ng/kg/min) and 3 patients had been on IV epoprostenol (mean dose 10 ng/kg/min) for an average duration of 113 ± 80 months. Although most patients who transitioned to inhaled treprostinil demonstrated no statistically significant worsening of hemodynamics or 6-minute walk distance, a minority demonstrated worsening of New York Heart Association functional class over a 7-month period. In conclusion, although transition of patients from IV/SQ prostanoids to inhaled treprostinil appears to be well tolerated in clinically stable patients, they should remain closely monitored for signs of clinical decompensation.

In the clinic. Pulmonary hypertension.

Section Editors Deborah Cotton, MD, MPH Darren Taichman, MD, PhD Sankey Williams, MD The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including PIER (Physicians’ Information and Education Resource) and MKSAP (Medical Knowledge and SelfAssessment Program). Annals of Internal Medicine editors develop In the Clinic from these primary sources in collaboration with the ACP’s Medical Education and Publishing divisions and with the assistance of science writers and physician writers. Editorial consultants from PIER and MKSAP provide expert review of the content. Readers who are interested in these primary resources for more detail can consult http://pier.acponline.org, http://www.acponline.org/products_services/ mksap/15/?pr31, and other resources referenced in each issue of In the Clinic.

Echocardiographic Estimation of Pulmonary Vascular Resistance in Chronic Thromboembolic Pulmonary Hypertension: Utility of Right Heart Doppler Measurements

The ratio of tricuspid regurgitation velocity divided by the velocity‐time integral of right ventricular outflow tract pulsed‐wave Doppler tracing (TRV/VTIRVOT) has been used to estimate pulmonary vascular resistance (PVR). However, this method has not been validated in chronic thromboembolic pulmonary hypertension (CTEPH). We assessed the utility of TRV/VTIRVOT in patients with CTEPH and PVR from 2 to 20 WU. All had right heart catheterization (RHC) within 2 days of echocardiography. TRV/VTIRVOT was calculated and RHC‐derived pressures, PVR, and cardiac outputs were recorded. Mean pulmonary artery pressure was 47 ± 12 mmHg, cardiac output: 4.2 ± 1.1 L/min, PVR: 9 ± 4 WU, right atrial pressure: 12 ± 6 mmHg. Mean VTIRVOT was 13 ± 5 cm; mean TRV was 4.2 ± 0.8 m/s, mean tricuspid regurgitation severity was 2.5 ± 0.8 (1 = trace, 2 = mild, 3 = moderate, 4 = severe). Regression analysis demonstrated a correlation between RHC PVR and TRV/VTIRVOT: PVR = 19.4 × (TRV/VTIRVOT) + 2.4 (r = 0.74, P < 0.001). However, Bland–Altman analysis found a poor degree of agreement between echo‐derived PVR and RHC PVR. We also studied 28 patients with non‐CTEPH pulmonary hypertension. Similar analysis revealed a regression equation of PVR = 20.1 × (TRV/VTIRVOT) + 0.3 (r = 0.57, P < 0.01). Conclusion: TRV/VTIRVOT is only marginally useful for estimating PVR in CTEPH (r = 0.74). Moreover, the regression equation in CTEPH differs significantly from previous studies in pulmonary hypertension. Reasons for this may include the markedly elevated PVR levels in this population and specific effects on VTIRVOT from CTEPH.

Mini-bronchoalveolar lavage quantitative polymerase chain reaction for diagnosis of methicillin-resistant Staphylococcus aureus pneumonia

Objectives:Methicillin-resistant Staphylococcus aureus is a common cause of ventilator-associated pneumonia and can be identified by the mecA gene that confers resistance. The objective was to develop a polymerase chain reaction assay for mecA using mini-bronchoalveolar lavage to allow rapid diagnosis of ventilator associated pneumonia attributable to methicillin-resistant Staphylococcus aureus. Design:Real-time quantitative polymerase chain reaction was developed using serial dilution of plasmids containing known amounts of mecA gene fragments. Specificity of molecular identification was based on the presence of the mecA gene and S. aureus-specific femA-SA gene, with absence of Staphylococcus epidermidis specific femA-SE. Setting and Patients:To validate the polymerase chain reaction, we compared it to mini-bronchoalveolar lavage quantitative cultures in 100 mechanically ventilated patients with suspected pneumonia. We derived a threshold value for defining a positive polymerase chain reaction based on a priori criteria of 100% sensitivity. We then tested the polymerase chain reaction using this threshold value on a separate cohort of 50 patients. Main Results:Polymerase chain reaction was able to detect mecA down to a copy number of three, with a high degree of correlation (r2 = .999). The area under the receiver-operating characteristic curve for polymerase chain reaction was 0.98 (95% confidence interval, 0.93–0.99). Using a cut-point of ≥421 for the polymerase chain reaction resulted in sensitivity of 100%, specificity of 87% (95% confidence interval 81%–94%), positive predictive value of 39% (95% confidence interval, 29%–49%), negative predictive value of 100%, and an overall correct classification rate of 89%. Applying the polymerase chain reaction with a cut-point of ≥421 to the second cohort resulted in a sensitivity of 100% and a specificity of 80%. Conclusions:Quantitative polymerase chain reaction of mecA combined with femA-SA and femA-SE detection was able to rapidly and accurately diagnose methicillin-resistant S. aureus.

Chronic thromboembolic pulmonary hypertension: detection, medical and surgical treatment approach, and current outcomes

Abstract Pulmonary hypertension due to chronic thromboembolic disease is potentially curable with pulmonary thromboendarterectomy surgery. As a result, it is important for clinicians to recognize and appropriately diagnose this form of pulmonary hypertension. Advances in this field with changes in surgical technique, the availability of PH-targeted medical therapy for select patient subgroups, and the development of balloon pulmonary angioplasty have broadened therapeutic options for patients. This review will examine what is known about the epidemiology and medical conditions placing patients at risk of developing this disease, will present an approach to evaluation of patients with suspected chronic thromboembolic disease, and will describe the surgical and non-surgical management of this unique patient population.

Prevalence of coronary artery–pulmonary artery collaterals in patients with chronic thromboembolic pulmonary hypertension

This study sought to determine the prevalence of coronary artery–pulmonary artery collaterals in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and to correlate their presence with the degree of clot burden. CTEPH is a treatable cause of severe pulmonary hypertension and right heart failure. Bronchopulmonary collateral vessels have been used as a supplementary diagnostic and prognostic tool for this disease. Coronary artery–pulmonary artery collaterals in this population have not been described. The coronary angiograms of 300 consecutive patients with CTEPH evaluated for pulmonary thromboendarterectomy (PTE) between January 1, 2007, and May 1, 2014, were examined. Of these patients, 259 (50% male; mean age, 58.3 ± 10.6 years) had cineangiographic images deemed adequate to definitively assess for the presence of coronary artery–pulmonary artery collaterals and were included in the final analyses. Pulmonary angiogram reports were reviewed for extent of pulmonary artery obstruction. The coronary angiograms of 259 age- and sex-matched control patients were also examined. Among 259 CTEPH patients with definitive imaging, 34 coronary artery–pulmonary artery collaterals were found in 28 patients (10.8%), versus 1 coronary artery–pulmonary artery collateral among control subjects (0.4%; P < 0.001). Compared with CTEPH patients without collaterals, patients with collaterals had a significantly higher prevalence of total occlusion of their right or left main pulmonary artery (P < 0.001) or lobar arteries (P < 0.001). In conclusion, the prevalence of coronary artery–pulmonary artery collaterals in CTEPH patients undergoing coronary angiography for possible PTE is approximately 11%. These vessels are associated with more severe pulmonary artery occlusion.

Baseline Body Mass Index Does Not Significantly Affect Outcomes After Pulmonary Thromboendarterectomy

BACKGROUND Obesity is a common comorbidity of patients with chronic thromboembolic pulmonary hypertension referred for pulmonary thromboendarterectomy, yet the effect of obesity on pulmonary thromboendarterectomy outcomes has not been well described. METHODS We conducted a retrospective cohort study in which 476 consecutive operations over a 3.5-year period were examined to determine the effects of obesity on outcomes. Patients were grouped into four categories based on body mass index (BMI): less than 22 kg/m2, 22 to 30 kg/m2, 30 to 40 kg/m2, and more than 40 kg/m2. RESULTS There were important differences in baseline pulmonary hemodynamics, with obese patients having significantly lower pulmonary vascular resistances than nonobese patients. All patients achieved a significant reduction in pulmonary vascular resistance, although the improvement was greatest in the lower BMI groups. The overall in-hospital mortality was 0.8%, and there were no differences in risk among BMI groups. Among the BMI groups, there were no differences in incidence of postoperative complications, including atrial fibrillation (overall 24.8%), reperfusion lung injury (overall 23.1%), and surgical site infection (overall 4.4%) or in median lengths of stay (including ventilator days, intensive care unit days, and postoperative length of stay). CONCLUSIONS Pulmonary thromboendarterectomy outcomes have continued to improve, and this surgery can safely be completed in obese patients, previously deemed to be at high risk for poor outcomes.

Case report: a patient with pulmonary arterial hypertension transitioning from a PDE-5 inhibitor to Riociguat

BackgroundWe present here the case of a patient with pulmonary arterial hypertension and NYHA Class II symptoms who transitioned from PDE-5i therapy to riociguat. No protocol currently exists for transitioning between these PAH medications.Case presentationA 59-year old male with a history of anorexigen use initially presented in 2008 and was felt to have non-operable small vessel disease. His care was transitioned to our center after insurance would not cover high-dose sildenafil in addition to ERA therapy.ConclusionThis case demonstrates a safe and successful transition from higher dose PDE-5is to riociguat with no interruption in therapy.

Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with several risk factors but is most frequently seen as a rare consequence of an acute pulmonary embolism. Surgical pulmonary thromboendarterectomy (PTE) is potentially curative for CTEPH with the best outcomes seen for the treatment of primarily proximal, accessible lobar or segmental disease. For surgically inoperable patients, percutaneous balloon pulmonary angioplasty (BPA) is feasible and has good short- to mid-term efficacy outcomes. This review focuses on the technique and outcomes associated with BPA which has emerged as a new therapeutic option for CTEPH.