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Dive into the research topics where Daniel Montgomery is active.

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Featured researches published by Daniel Montgomery.


American Journal of Cardiology | 2008

Association Between Admission Neutrophil to Lymphocyte Ratio and Outcomes in Patients With Acute Coronary Syndrome

Umesh Tamhane; Sanjay Aneja; Daniel Montgomery; Eva-Kline Rogers; Kim A. Eagle; Hitinder S. Gurm

The neutrophil/lymphocyte ratio (NLR) has recently been described as a predictor of mortality in patients who undergo percutaneous coronary intervention. The aim of this study was to investigate the utility of admission NLRs in predicting outcomes in patients with acute coronary syndromes (ACS). A total of 2,833 patients admitted to the University of Michigan Health System with diagnoses of ACS from December 1998 to October 2004 were followed. Patients were divided into tertiles according to NLR. The primary end point was all-cause in-hospital and 6-month mortality. The ACS cohort comprised 564 patients with ST-segment elevation myocardial infarctions and 2,269 patients with non-ST-segment elevation ACS. Patients in tertile 3 had higher in-hospital (8.5% vs 1.8%) and 6-month (11.5% vs 2.5%) mortality compared with those in tertile 1 (p <0.001). After adjusting for Global Registry of Acute Coronary Events risk profile, patients in the highest tertile were at an exaggerated risk for in-hospital (odds ratio 2.04, p = 0.013) and 6-month (odds ratio 3.88, p <0.001) mortality. Admission NLR is an independent predictor of in-hospital and 6-month mortality in patients with ACS. This relatively inexpensive marker of inflammation can aid in the risk stratification and prognosis of patients diagnosed with ACS.


Journal of the American College of Cardiology | 1993

Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction☆☆☆

Mark R. Starling; Marvin M. Kirsh; Daniel Montgomery; Milton D. Gross

OBJECTIVES We tested the hypotheses that left ventricular chamber elastance would detect impaired contractile function in patients with long-term mitral regurgitation and a normal ejection fraction and that these patients would have unique temporal left ventricular size and ejection fraction responses to mitral valve surgery. BACKGROUND Although it has been suggested that left ventricular contractile function may begin deteriorating in patients with long-term mitral regurgitation whereas ejection fraction remains normal, no data exist in humans. METHODS We studied 11 control patients and 28 patients with long-term mitral regurgitation using micromanometer-measured pressures, biplane contrast cineventriculography and radionuclide angiography under control conditions and with alterations in load during right atrial pacing to calculate left ventricular chamber elastance and myocardial stiffness. RESULTS The patients with mitral regurgitation were classified into subgroups: Group I, normal contractile function; Group II, impaired contractile function (reduced Emax) but normal ejection fraction, and Group III, impaired contractile function (reduced Emax) with reduced systolic myocardial stiffness. Twenty-two of the patients with mitral regurgitation underwent mitral valve surgery. In Group I, comparable decreases in left ventricular volume indexes (p < 0.01 and p = 0.05, respectively) were associated with no change in ejection fraction at 3 months and 1 year. In contrast, in Group II, reductions in volume indexes (p < 0.0001 and p < 0.001) were associated with a short-term decrease in ejection fraction (p < 0.001) that recovered at 1 year (p < 0.01 vs. short-term). Finally, in Group III, variable responses in volume indexes were associated with a consistent decrease in ejection fraction at 3 months and 1 year. CONCLUSIONS An analysis of left ventricular chamber elastance provides data to support the concepts that 1) contractile function is impaired in some patients with long-term mitral regurgitation and a normal ejection fraction, 2) impaired contractile function may not be irreversible in all of these patients, and 3) an earlier consideration of mitral valve surgery may be warranted to preserve contractile function in these patients.


Journal of the American College of Cardiology | 2015

Presentation, diagnosis, and outcomes of acute aortic dissection: 17-year trends from the international registry of acute aortic dissection

Linda Pape; Mazen Awais; Elise M. Woznicki; Toru Suzuki; Santi Trimarchi; Arturo Evangelista; Truls Myrmel; Magnus Larsen; Kevin M. Harris; Kevin L. Greason; Marco Di Eusanio; Eduardo Bossone; Daniel Montgomery; Kim A. Eagle; Christoph Nienaber; Eric M. Isselbacher; Patrick T. O'Gara

BACKGROUND Diagnosis, treatment, and outcomes of acute aortic dissection (AAS) are changing. OBJECTIVES This study examined 17-year trends in the presentation, diagnosis, and hospital outcomes of AAD from the International Registry of Acute Aortic Dissection (IRAD). METHODS Data from 4,428 patients enrolled at 28 IRAD centers between December 26, 1995, and February 6, 2013, were analyzed. Patients were divided according to enrollment date into 6 equal groups and by AAD type: A (n = 2,952) or B (n = 1,476). RESULTS There was no change in the presenting complaints of severe or worst-ever pain for type A and type B AAD (93% and 94%, respectively), nor in the incidence of chest pain (83% and 71%, respectively). Use of computed tomography (CT) for diagnosis of type A increased from 46% to 73% (p < 0.001). Surgical management for type A increased from 79% to 90% (p < 0.001). Endovascular management of type B increased from 7% to 31% (p < 0.001). Type A in-hospital mortality decreased significantly (31% to 22%; p < 0.001), as surgical mortality (25% to 18%; p = 0.003). There was no significant trend in in-hospital mortality in type B (from 12% to 14%). CONCLUSIONS Presenting symptoms and physical findings of AAD have not changed significantly. Use of chest CT increased for type A. More patients in both groups were managed with interventional procedures: surgery in type A and endovascular therapy in type B. A significant decrease in overall in-hospital mortality was seen for type A but not for type B.


The Journal of Thoracic and Cardiovascular Surgery | 2010

Role of age in acute type A aortic dissection outcome: report from the International Registry of Acute Aortic Dissection (IRAD).

Santi Trimarchi; Kim A. Eagle; Christoph Nienaber; Vincenzo Rampoldi; Frederik H.W. Jonker; Carlo de Vincentiis; Alessandro Frigiola; Lorenzo Menicanti; Thomas C. Tsai; Jim Froehlich; Arturo Evangelista; Daniel Montgomery; Eduardo Bossone; Jeanna V. Cooper; Jin Li; Michael G. Deeb; Gabriel Meinhardt; Thoralf M. Sundt; Eric M. Isselbacher

OBJECTIVE The increasing life expectancy of the population will likely be accompanied by a rise in the incidence of acute type A aortic dissection. However, because of an increased risk of cardiac surgery in an elderly population, it is important to define when, if at all, the risks of aortic repair outweigh the risk of death from unoperated type A aortic dissection. METHODS We analyzed 936 patients with type A aortic dissection enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2004. Patients with type A aortic dissection were categorized according to patient age by decade and by surgical versus medical management, and outcomes of both management types were investigated in the different age groups. RESULTS The rate of surgical aortic repair decreased progressively with age, whereas surgical mortality significantly increased with age. Age 70 years or more was an independent predictor for mortality (38.2% vs 26.0%; P < .0001, odds ratio 1.73). The in-hospital mortality rate was significantly lower after surgical management compared with medical management until the age of 80 years. For patients aged 80 to 90 years, the in-hospital mortality appeared to be lower after surgical management (37.9% vs 55.2%; P = .188); however, this failed to reach clinical significance owing to the limited patient number in this age group. CONCLUSIONS Although the surgical mortality significantly increased with increased age, surgical management was still associated with significantly lower in-hospital mortality rates compared with medical management until the age of 80 years. Surgery may decrease the in-hospital mortality rate for octogenarians with type A aortic dissection and might be considered in all patients with type A aortic dissection regardless of age.


Circulation | 1987

Load independence of the rate of isovolumic relaxation in man.

Mark R. Starling; Daniel Montgomery; G. B. J. Mancini; Richard A. Walsh

This investigation was designed to determine whether the rate of isovolumic left ventricular pressure decline is affected by load in man. Fourteen patients were instrumented with micromanometer left ventricular and right atrial pacing catheters to maintain a constant heart rate during control conditions and infusion of methoxamine or nitroprusside. The isovolumic relaxation period was defined as the time from peak (-)dP/dt to 5 mm Hg above left ventricular end-diastolic pressure of the following beat. The rate of isovolumic relaxation was calculated as time constants (Tau) from the linear regression of natural log pressure vs time (Tln) and instantaneous (-)dP/dt vs pressure (TD), which includes a variable asymptote (PB). The mean heart rates and average (+)dP/dt values normalized at 40 mm Hg development pressure (DP40) did not differ significantly, despite 33% and 43% increases in left ventricular peak and end-diastolic pressures during the infusion of methoxamine (p less than .001 and p less than .01, respectively) and 24% and 29% decreases during the infusion of nitroprusside (p less than .001 and p less than .01, respectively). The average Tln and TD values were not significantly affected by these alterations in load. In two patients, an inverse linear relationship was demonstrated between decreases in Tau and increases in contractile state produced by an infusion of dobutamine, as shown by correlation of Tln and TD with (+)dP/dt/DP40 (r = -.88 and -.83, respectively). We conclude that the time constants of left ventricular isovolumic relaxation are unaffected by modest alterations in loading conditions in man when heart rate is maintained constant.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of the American College of Cardiology | 2015

Original InvestigationPresentation, Diagnosis, and Outcomes of Acute Aortic Dissection: 17-Year Trends From the International Registry of Acute Aortic Dissection

Linda Pape; Mazen Awais; Elise M. Woznicki; Toru Suzuki; Santi Trimarchi; Arturo Evangelista; Truls Myrmel; Magnus Larsen; Kevin M. Harris; Kevin L. Greason; Marco Di Eusanio; Eduardo Bossone; Daniel Montgomery; Kim A. Eagle; Christoph Nienaber; Eric M. Isselbacher; Patrick T. O'Gara

BACKGROUND Diagnosis, treatment, and outcomes of acute aortic dissection (AAS) are changing. OBJECTIVES This study examined 17-year trends in the presentation, diagnosis, and hospital outcomes of AAD from the International Registry of Acute Aortic Dissection (IRAD). METHODS Data from 4,428 patients enrolled at 28 IRAD centers between December 26, 1995, and February 6, 2013, were analyzed. Patients were divided according to enrollment date into 6 equal groups and by AAD type: A (n = 2,952) or B (n = 1,476). RESULTS There was no change in the presenting complaints of severe or worst-ever pain for type A and type B AAD (93% and 94%, respectively), nor in the incidence of chest pain (83% and 71%, respectively). Use of computed tomography (CT) for diagnosis of type A increased from 46% to 73% (p < 0.001). Surgical management for type A increased from 79% to 90% (p < 0.001). Endovascular management of type B increased from 7% to 31% (p < 0.001). Type A in-hospital mortality decreased significantly (31% to 22%; p < 0.001), as surgical mortality (25% to 18%; p = 0.003). There was no significant trend in in-hospital mortality in type B (from 12% to 14%). CONCLUSIONS Presenting symptoms and physical findings of AAD have not changed significantly. Use of chest CT increased for type A. More patients in both groups were managed with interventional procedures: surgery in type A and endovascular therapy in type B. A significant decrease in overall in-hospital mortality was seen for type A but not for type B.


Circulation | 2011

Sensitivity of the Aortic Dissection Detection Risk Score, a Novel Guideline-Based Tool for Identification of Acute Aortic Dissection at Initial Presentation Results From the International Registry of Acute Aortic Dissection

Adam M. Rogers; Luke K. Hermann; Anna M. Booher; Christoph Nienaber; David M. Williams; Ella A. Kazerooni; James B. Froehlich; Patrick T. O'Gara; Daniel Montgomery; Jeanna V. Cooper; Kevin M. Harris; Stuart Hutchison; Arturo Evangelista; Eric M. Isselbacher; Kim A. Eagle

Background— In 2010, the American Heart Association and American College of Cardiology released guidelines for the diagnosis and management of patients with thoracic aortic disease, which identified high-risk clinical features to assist in the early detection of acute aortic dissection. The sensitivity of these risk markers has not been validated. Methods and Results— We examined patients enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2009. The number of patients with confirmed acute aortic dissection who presented with 1 or more of 12 proposed clinical risk markers was determined. An aortic dissection detection (ADD) risk score of 0 to 3 was calculated on the basis of the number of risk categories (high-risk predisposing conditions, high-risk pain features, high-risk examination features) in which patients met criteria. The ADD risk score was tested for sensitivity. Of 2538 patients with acute aortic dissection, 2430 (95.7%) were identified by 1 or more of 12 proposed clinical risk markers. With the use of the ADD risk score, 108 patients (4.3%) were identified as low risk (ADD score 0), 927 patients (36.5%) were intermediate risk (ADD score 1), and 1503 patients (59.2%) were high risk (ADD score 2 or 3). Among 108 patients with no clinical risk markers present (ADD score 0), 72 had chest x-rays recorded, of which 35 (48.6%) demonstrated a widened mediastinum. Conclusions— The clinical risk markers proposed in the 2010 thoracic aortic disease guidelines and their application as part of the ADD risk score comprise a highly sensitive clinical tool for the detection of acute aortic dissection.


American Journal of Cardiology | 2012

Type-selective benefits of medications in treatment of acute aortic dissection (from the International Registry of Acute Aortic Dissection [IRAD]).

Toru Suzuki; Eric M. Isselbacher; Christoph Nienaber; Reed E. Pyeritz; Kim A. Eagle; Thomas T. Tsai; Jeanna V. Cooper; James L. Januzzi; Alan C. Braverman; Daniel Montgomery; Rossella Fattori; Linda Pape; Kevin M. Harris; Anna M. Booher; Jae K. Oh; Mark D. Peterson; Vijay S. Ramanath; James B. Froehlich

The effects of medications on the outcome of aortic dissection remain poorly understood. We sought to address this by analyzing the International Registry of Acute Aortic Dissection (IRAD) global registry database. A total of 1,301 patients with acute aortic dissection (722 with type A and 579 with type B) with information on their medications at discharge and followed for ≤5 years were analyzed for the effects of the medications on mortality. The initial univariate analysis showed that use of β blockers was associated with improved survival in all patients (p = 0.03), in patients with type A overall (p = 0.02), and in patients with type A who received surgery (p = 0.006). The analysis also showed that use of calcium channel blockers was associated with improved survival in patients with type B overall (p = 0.02) and in patients with type B receiving medical management (p = 0.03). Multivariate models also showed that the use of β blockers was associated with improved survival in those with type A undergoing surgery (odds ratio 0.47, 95% confidence interval 0.25 to 0.90, p = 0.02) and the use of calcium channel blockers was associated with improved survival in patients with type B medically treated patients (odds ratio 0.55, 95% confidence interval 0.35 to 0.88, p = 0.01). In conclusion, the present study showed that use of β blockers was associated with improved outcome in all patients and in type A patients (overall as well as in those managed surgically). In contrast, use of calcium channel blockers was associated with improved survival selectively in those with type B (overall and in those treated medically). The use of angiotensin-converting enzyme inhibitors did not show association with mortality.


The American Journal of Medicine | 2013

The IRAD Classification System for Characterizing Survival after Aortic Dissection

Anna M. Booher; Eric M. Isselbacher; Christoph Nienaber; Santi Trimarchi; Arturo Evangelista; Daniel Montgomery; James B. Froehlich; Marek Ehrlich; Jae K. Oh; James L. Januzzi; Patrick T. O'Gara; Thoralf M. Sundt; Kevin M. Harris; Eduardo Bossone; Reed E. Pyeritz; Kim A. Eagle

BACKGROUND The classification of aortic dissection into acute (<14 days from symptom onset) versus chronic (≥14 days) is based on survival estimates of patients treated decades before modern diagnostic and treatment modalities were available. A new classification of aortic dissection in the current era may provide clinicians with a more precise method of characterizing the interaction of time, dissection location, and treatment type with survival. METHODS We developed separate Kaplan-Meier survival curves for Type A and Type B aortic dissection using data from the International Registry of Aortic Dissection (IRAD). Daily survival was stratified based on type of therapy provided: medical therapy alone (medical), nonsurgical intervention plus medical therapy (endovascular), and open surgery plus medical therapy (surgical). The log-rank statistic was used to compare the survival curves of each management type within Type A and Type B aortic dissection. RESULTS There were 1815 patients included, 67.3% male with mean age 62.0 ± 14.2 years. When survival curves were constructed, 4 distinct time periods were noted: hyperacute (symptom onset to 24 hours), acute (2-7 days), subacute (8-30 days), and chronic (>30 days). Overall survival was progressively lower through the 4 time periods. CONCLUSIONS This IRAD classification system can provide clinicians with a more robust method of characterizing survival after aortic dissection over time than previous methods. This system will be useful for treating patients, counseling patients and families, and studying new diagnostic and treatment methods.


Circulation | 2011

Correlates of Delayed Recognition and Treatment of Acute Type A Aortic Dissection The International Registry of Acute Aortic Dissection (IRAD)

Kevin M. Harris; Craig Strauss; Kim A. Eagle; Alan T. Hirsch; Eric M. Isselbacher; Thomas T. Tsai; Hadas Shiran; Rossella Fattori; Arturo Evangelista; Jeanna V. Cooper; Daniel Montgomery; James B. Froehlich; Christoph Nienaber

Background— In acute aortic dissection, delays exist between presentation and diagnosis and, once diagnosed, definitive treatment. This study aimed to define the variables associated with these delays. Methods and Results— Acute aortic dissection patients enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and January 2007 were evaluated for factors contributing to delays in presentation to diagnosis and in diagnosis to surgery. Multiple linear regression was performed to determine relative delay time ratios (DTRs) for individual correlates. The median time from arrival at the emergency department to diagnosis was 4.3 hours (quartile 1–3, 1.5–24 hours; n=894 patients) and from diagnosis to surgery was 4.3 hours (quartile 1–3, 2.4–24 hours; n=751). Delays in acute aortic dissection diagnosis occurred in female patients; those with atypical symptoms that were not abrupt or did not include chest, back, or any pain; patients with an absence of pulse deficit or hypotension; or those who initially presented to a nontertiary care hospital (all P<0.05). The largest relative DTRs were for fever (DTR=5.11; P<0.001) and transfer from nontertiary hospital (DTR=3.34; P<0.001). Delay in time from diagnosis to surgery was associated with a history of previous cardiac surgery, presentation without abrupt or any pain, and initial presentation to a nontertiary care hospital (all P<0.001). The strongest factors associated with operative delay were prolonged time from presentation to diagnosis (DTR=1.35; P<0.001), race other than white (DTR=2.25; P<0.001), and history of coronary artery bypass surgery (DTR=2.81; P<0.001). Conclusions— Improved physician awareness of atypical presentations and prompt transport of acute aortic dissection patients could reduce crucial time variables.

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Arturo Evangelista

Autonomous University of Barcelona

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