Gadolinium-enhanced cardiovascular magnetic resonance: administered dose in relationship to united states food and drug administration (FDA) guidelines

Purpose

Myocardial late gadolinium enhancement was originally validated using higher than label-recommended doses of gadolinium chelate. The objective of this study was to evaluate available evidence for various gadolinium dosing regimens used for CMR. The relationship of gadolinium dose warnings (due to nephrogenic systemic fibrosis) announced in 2008 to gadolinium dosing regimens was also examined.

Methods

We conducted a meta-analysis of peer reviewed publications from January, 2004 to December, 2010. Major subject search headings (MeSh) terms from the National Library of Medicine''s PubMed were: contrast media, gadolinium, heart, magnetic resonance imaging; searches were limited to human studies with abstracts published in English. Case reports, review articles, editorials, MRA related papers and all reports that did not indicate gadolinium type or weight-based dose were excluded. For all included references, full text was available to determine the total administered gadolinium dose on a per kg basis. Average and median dose values were weighted by the number of subjects in each study.

Results

399 publications were identified in PubMed; 233 studies matched the inclusion criteria, encompassing 19,934 patients with mean age 54.2 ± 11.4 (range 9.3 to 76 years). 34 trials were related to perfusion testing and 199 to myocardial late gadolinium enhancement. In 2004, the weighted-median and weighted-mean contrast dose were 0.15 and 0.16 ± 0.06 mmol/kg, respectively. Median contrast doses for 2005-2010 were: 0.2 mmol/kg for all years, respectively. Mean contrast doses for the years 2005-2010 were: 0.19 ± 0.03, 0.18 ± 0.04, 0.18 ± 0.10, 0.18 ± 0.03, 0.18 ± 0.04 and 0.18 ± 0.04 mmol/kg, respectively (p for trend, NS). Gadopentetate dimeglumine was the most frequent gadolinium type [114 (48.9%) studies]. No change in mean gadolinium dose was present before, versus after the Food and Drug Administration (FDA) black box warning (p > 0.05). Three multi-center dose ranging trials have been published for cardiac MRI applications.

Conclusion

CMR studies in the peer-reviewed published literature routinely use higher gadolinium doses than regulatory agencies indicated in the package leaflet. Clinical trials should be supported to determine the appropriate doses of gadolinium for CMR studies.     

Predictors of nocturnal oxygen desaturation in pulmonary arterial hypertension

Background:Sleep may be associated with significant respiratory compromise in patients with lung disease and can result in hypoxia. In patients with pulmonary arterial hypertension (PAH), nocturnal desaturation may not be reflected in daytime evaluations of oxygenation and can lead to worsening pulmonary hemodynamics. The study was conducted to determine the prevalence and significance of nocturnal oxygen desaturation in patients with PAH.Methods:A cross-sectional study conducted at the Cleveland Clinic. Patients were followed up at our institution except for the overnight oximetry study done at home. Data regarding degree of nocturnal desaturation, demographics, hemodynamics, pulmonary function, and functional capacity were collected.Results:Forty-three patients (mean age, 47.9 ± 13.5 years [± SD]; 36 women and 7 men) underwent nocturnal oximetry. The etiology of PAH included idiopathic PAH (88%) and PAH associated with connective tissue diseases (12%). The majority of patients were New York Heart Association functional class II (42%) or III (53%). Thirty patients (69.7%) spent > 10% of sleep time with oxygen saturation by pulse oximetry < 90%. Desaturators were older (p = 0.024) and had higher hemoglobin (p = 0.002). Sixteen of 27 patients (59%) without desaturation < 90% during a 6-min walk test were nocturnal desaturators. Nocturnal desaturators had higher brain natriuretic protein (p = 0.004), lower cardiac index (p = 0.03), and higher mean right atrial pressure (p = 0.09), mean pulmonary artery pressure, and pulmonary vascular resistance. On echocardiography, desaturators were more likely to have moderate or severe right ventricular dilation (p = 0.04) and pericardial effusion. Only one patient had significant sleep apnea.Conclusions:Nocturnal hypoxemia is common in PAH patients and correlates with advanced pulmonary hypertension and right ventricular dysfunction. Approximately 60% patients without exertional hypoxia had nocturnal desaturation. Overnight oximetry should be considered in the routine workup of PAH patients who do not demonstrate exertional desaturation.     

Update in ARDS management: recent randomized controlled trials that changed our practice

In the last 7 years, 14 randomized controlled trials in patients with acute respiratory distress syndrome (ARDS) have shown that: Mechanical ventilation with a tidal volume of 6 mL/kg of predicted body weight is better than mechanical ventilation with a tidal volume of 12 mL/kg of predicted body weight. Prone positioning improves oxygenation but poses safety concerns. A high level of positive end-expiratory pressure does not improve survival. High-frequency oscillatory ventilation is in theory the ideal "lung-protective" method, but its benefits have not been proven. No drug therapy has been shown to improve survival in patients with ARDS. Exogenous surfactant may improve oxygenation but has no significant effect on the death rate or length of use of mechanical ventilation. Low-dose inhaled nitric oxide has no substantial impact on the duration of ventilatory support or on the death rate. Partial liquid ventilation may be beneficial in young patients with acute lung injury or ARDS, although further study is needed to confirm this.     

Persistent pigmented purpuric eruption associated with mycosis fungoides: a case report and review of the literature

A purpuric eruption may be an unusual early manifestation of mycosis fungoides (MF). On the other hand, persistent pigmented purpuric dermatoses (PPPD) may, occasionally, evolve to cutaneous T-cell lymphoma. Coexistence of these two conditions has been reported, but it is extremely rare. We present the case of an elderly woman with a long-standing pruritic, pigmented purpuric eruption. On 1-year follow-up, histological features suggesting early MF were observed and molecular analysis of the rearrangement of T-cell receptor genes revealed clonality. Our patient may represent a case of PPPD evolving to MF, a case of MF clinically featuring PPPD, or an intermediate condition in a nosological continuity extending from PPPD to MF. A persistent pigmented purpuric eruption may rarely be a harbinger of cutaneous T-cell lymphoma. Therefore, vigilant long-term follow-up of PPPD is highly recommended.