Christoph Knapitsch

Dr. Christoph Knapitsch

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Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 October 2024 in Diagnostics
Verified
Journal Article
Open access
PDF file
CDChristian Dinges
Christian Dinges
MHMatthias Hammerer
Matthias Hammerer
NSNikolaos Schörghofer
Nikolaos Schörghofer
CKChristoph Knapitsch
Christoph Knapitsch
GHGretha Hecke
Gretha Hecke
BSBernhard Scharinger
Bernhard Scharinger
Background: Sarcopenia, characterized by the loss of skeletal muscle mass, is an emerging comorbidity associated with poor outcomes in cardiovascular surgery. Its impact on mortality in patients undergoing valve surgery for infective endocarditis (IE) remains underexplored. This study investigates the relationship between sarcopenia, measured by the Psoas muscle area index (PMAi), and mortality in patients with IE undergoing valve surgery. Materials and Methods: We retrospectively analyzed 68 patients with IE who underwent valve surgery at a tertiary care center from 2013 to 2021. Sarcopenia was defined as being in the lowest quartile of PMAi, measured via preoperative computed tomography (CT). Baseline characteristics, survival outcomes, and factors influencing mortality were analyzed using Kaplan–Meier survival curves and Cox proportional hazards regression. The predictive value of PMAi for 1-year and 3-year mortality was assessed via receiver operating characteristic (ROC) curves. Results: Sarcopenia was strongly associated with increased mortality at both 1-year (HR: 0.378, p = 0.010) and 3-year follow-ups (HR: 0.457, p = 0.012). Female sex (OR: 275.748, p < 0.001) and older age (OR: 9.995, p = 0.003) were significant predictors of sarcopenia. Chronic kidney insufficiency (CKI) and the use of heart failure medication therapy also significantly impacted survival outcomes. Conclusions: Sarcopenia is a strong independent predictor of short- and mid-term mortality in patients undergoing valve surgery for IE. Routine radiological assessment of sarcopenia using PMAi could improve risk stratification and guide preoperative interventions. Tailored management strategies, especially in older women and patients with CKI, may enhance outcomes in this high-risk population.

12 November 2024 in Diagnostics
Verified
Journal Article
Open access
PDF file
CDChristian Dinges
Christian Dinges
EBElke Boxhammer
Elke Boxhammer
IKIris Kremser
Iris Kremser
KGKatja Gansterer
Katja Gansterer
JSJohannes Steindl
Johannes Steindl
BSBernhard Scharinger
Bernhard Scharinger
Background: Infective endocarditis (IE) poses significant challenges in cardiovascular medicine, often necessitating valvular surgery to manage severe complications. Postoperative acute kidney injury (AKI) is a notable complication affecting patient outcomes. While clinical and procedural factors have been well studied, the role of radiological renal artery parameters in AKI risk remains underexplored. Methods: This retrospective study analyzed 80 patients with IE who underwent valvular surgery from 2013 to 2021, focusing on postoperative AKI as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Radiological parameters, including renal artery calcification, renal ostial calcification, the presence of renal infarctions, and additional arteries, were assessed using preoperative computed tomography (CT). Statistical analyses included binary logistic and linear regression models, Kaplan–Meier survival curves, and Cox proportional hazard regression to explore associations between these parameters and AKI incidence, creatinine levels, and mortality. Results: Out of 80 patients, 31 (38.8%) developed AKI. No significant differences were found in baseline characteristics or radiological parameters between the AKI+ and AKI− groups. Binary logistic and linear regression analyses revealed no substantial relationship between anatomical factors and AKI risk or creatinine levels. However, Cox regression identified “additional renal artery” as a significant predictor of 1-month mortality (HR: 1.747, 95% CI: 1.024–2.979, p = 0.041) but not for 6- or 12-month mortality. Conclusions: Radiological anatomical factors, including calcifications and additional arteries, did not significantly impact AKI risk in IE patients undergoing valvular surgery. However, the presence of additional arteries was associated with increased short-term mortality. These findings suggest the need for further research to elucidate factors contributing to AKI and mortality in this context.

7 April 2026 in Insights into Imaging
Verified
Journal Article
Open access
EBElke Boxhammer
Elke Boxhammer
MHMatthias Hammerer
Matthias Hammerer
NSNikolaos Schörghofer
Nikolaos Schörghofer
NCNikolaus Clodi
Nikolaus Clodi
EPErika Prinz
Erika Prinz
BSBernhard Scharinger
Bernhard Scharinger
Objective: Pulmonary hypertension (PH) significantly affects outcomes after transcatheter aortic valve implantation (TAVI), with sex-specific differences indicating the need for tailored strategies. This study investigated the predictive value of CT-derived main pulmonary artery (MPA) dimensions and ratios, focusing on diagnostic accuracy and prognostic relevance in male and female TAVI patients. Materials and methods: A retrospective analysis of 526 patients (263 male, 263 female) undergoing TAVI was performed. PH was defined echocardiographically according to European Society of Cardiology (ESC) guidelines. Pre-procedural CT measurements of MPA, ascending aorta (AA), and derived ratios (e.g., MPA/AA) were analyzed. Sex-specific cut-offs were determined using area under the receiver operating characteristic (AUROC) analyses and validated with survival curves and Cox regression. Results: MPA and its ratios outperformed right and left pulmonary artery metrics in detecting PH. Overall cut-offs were MPA ≥ 29.5 mm and MPA/AA ≥ 0.76. In men, elevated MPA or MPA/AA showed strong associations with PH, whereas in women, higher cut-offs (MPA ≥ 30.0 mm; MPA/AA ≥ 0.86) were less diagnostically useful. Importantly, the MPA/AA ratio predicted long-term survival only in men (hazard ratio (HR) = 1.857, p = 0.006), underlining its limited prognostic role in females. Conclusion: CT-derived pulmonary artery metrics are valuable for predicting PH and survival in male TAVI patients. Incorporating the MPA/AA ratio into clinical practice may improve risk stratification in men, while limited diagnostic utility in women highlights the need for alternative markers. Sex-specific approaches should be pursued to optimize outcomes across all PH etiologies. Critical relevance statement: CT-derived pulmonary artery metrics reliably predict PH and long-term survival after TAVI, particularly in men, emphasizing their diagnostic and prognostic value while underscoring the need for sex-specific thresholds and alternative markers in women. Key Points: PH impacts TAVI outcomes, yet sex-specific radiological predictors remain insufficiently investigated. The pulmonary artery to AA ratio predicted survival in men but showed no prognostic value for women. Implementing sex-specific imaging assessments improves risk stratification in men, highlighting the need for distinct diagnostic strategies for women. Graphical

Verified
Journal Article
Open access
PDF file
MHMatthias Hammerer
Matthias Hammerer
PHPhilipp Hasenbichler
Philipp Hasenbichler
NSNikolaos Schörghofer
Nikolaos Schörghofer
CKChristoph Knapitsch
Christoph Knapitsch
NCNikolaus Clodi
Nikolaus Clodi
BSBernhard Scharinger
Bernhard Scharinger
Background: Transcatheter aortic valve implantation (TAVI) has revolutionized the treatment of severe aortic valve stenosis (AS). Balloon post-dilatation (PD) remains an important procedural step to optimize valve function by resolving incomplete valve expansion, which may lead to paravalvular regurgitation and other potentially adverse effects. There are only limited data on the predictors, incidence, and clinical impact of PD during TAVI. Methods: This retrospective, single-center study analyzed 585 patients who underwent TAVI (2016–2022). Pre-procedural evaluations included transthoracic echocardiography and CT angiography to assess key parameters, including the aortic valve calcium score (AVCS); aortic valve calcium density (AVCd); aortic valve maximal systolic transvalvular flow velocity (AV Vmax); and aortic valve mean systolic pressure gradient (AV MPG). We identified imaging predictors of PD and evaluated associated clinical outcomes by analyzing procedural endpoints (according to VARC-3 criteria) and long-term survival. Results: PD was performed on 67 out of 585 patients, with elevated AV Vmax (OR: 1.424, 95% CI: 1.039–1.950; p = 0.028) and AVCd (OR: 1.618, 95% CI: 1.227–2.132; p = 0.001) emerging as a significant independent predictor for PD in TAVI. Kaplan–Meier survival analysis revealed no significant differences in short- and mid-term survival between patients who underwent PD and those who did not. Interestingly, patients requiring PD exhibited a lower incidence of adverse events regarding major vascular complications, permanent pacemaker implantations and stroke. Conclusions: The study highlights AV Vmax and AVCd as key predictors of PD. Importantly, PD was not associated with increased procedural adverse events and did not predict adverse events in this contemporary cohort.

11 August 2026 in Medical Sciences
Verified
Journal Article
Open access
PDF file
NSNikolaos Schörghofer
Nikolaos Schörghofer
NCNikolaus Clodi
Nikolaus Clodi
GHGretha Hecke
Gretha Hecke
MHMatthias Hammerer
Matthias Hammerer
AKAlexander Kupferthaler
Alexander Kupferthaler
CKChristoph Knapitsch
Christoph Knapitsch
Background/Objectives: Pleural effusions are frequently encountered on pre-procedural computed tomography (CT) scans in patients undergoing transcatheter aortic valve implantation (TAVI). While often regarded as a marker of congestion and advanced cardiovascular disease, their clinical and prognostic significance in contemporary TAVI populations remains poorly understood. This study investigated the relationship between AI-derived pleural effusion volume, cardiovascular dysfunction, and long-term mortality after TAVI. Methods: Consecutive patients undergoing transfemoral TAVI between 2016 and 2022 who had available pre-procedural CT imaging were retrospectively included. Pleural effusion volume was quantified using an artificial intelligence-based segmentation workflow and analyzed as categorical, continuous, log-transformed, and threshold-based variables. Associations with clinical and echocardiographic characteristics were evaluated using Spearman correlation analyses. Long-term mortality was assessed using Kaplan–Meier analysis, Cox proportional hazards regression, and restricted cubic spline models. Results: A total of 470 patients were included (median age 82 years, 50.9% male). Pleural effusion was present in 124 patients (26.38%), including 73 (15.53%) with small, 26 (5.53%) with moderate, and 25 (5.32%) with larger effusions. Increasing pleural effusion volume was associated with atrial fibrillation (AF) (rho = 0.189, p < 0.001), higher systolic pulmonary artery pressure (rho = 0.224, p < 0.001), lower tricuspid annular plane systolic excursion (rho = −0.236, p < 0.001), impaired right ventricular–pulmonary arterial coupling (rho = −0.267, p < 0.001), lower stroke volume index (rho = −0.229, p < 0.001), and reduced left ventricular ejection fraction (rho = −0.221, p < 0.001). Despite these associations, pleural effusion volume was not associated with long-term mortality in univariable analyses, multivariable Cox regression models, or restricted cubic spline analyses. In the fully adjusted model, log-transformed pleural effusion volume was not independently associated with mortality (HR 1.00, 95% CI 0.93–1.08; p = 0.976). Conclusions: AI-derived pleural effusion volume is associated with markers of cardiovascular congestion and adverse hemodynamic remodeling in patients undergoing TAVI. However, pleural effusion burden does not independently predict long-term mortality, suggesting that its value lies primarily in phenotyping cardiovascular disease severity rather than risk stratification.

18 August 2026 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
GHGretha Hecke
Gretha Hecke
NCNikolaus Clodi
Nikolaus Clodi
BSBernhard Scharinger
Bernhard Scharinger
MHMatthias Hammerer
Matthias Hammerer
LPLaura Preuss
Laura Preuss
NSNikolaos Schörghofer
Nikolaos Schörghofer
Background: Pericardial effusion is a common finding on pre-procedural computed tomography (CT) in patients undergoing transcatheter aortic valve implantation (TAVI). However, its clinical significance remains uncertain. Using artificial intelligence (AI)-based image analysis, we sought to determine whether pericardial effusion represents an incidental imaging finding, a marker of hemodynamic burden, or a prognostically relevant phenotype. Methods: This retrospective single-center study included 470 consecutive patients undergoing TAVI for severe aortic stenosis. Pericardial effusion volume was quantified using an AI-based CT segmentation workflow and categorized as no effusion (0 mL), trace effusion (>0–<5 mL), small effusion (5–<30 mL), or larger effusion (≥30 mL). Associations with baseline clinical and echocardiographic characteristics were assessed. Long-term mortality was evaluated using Kaplan–Meier analysis, Cox regression models, and restricted cubic spline analyses. Results: Detectable pericardial effusion was present in 276 patients (58.7%), although larger effusions were uncommon (5.1%). Increasing pericardial effusion volume was associated with a higher prevalence of atrial fibrillation (p = 0.001), higher systolic pulmonary artery pressure (p = 0.004), and lower TAPSE/sPAP ratios (p = 0.007). In contrast, left ventricular ejection fraction and transvalvular gradients did not differ across effusion categories. During long-term follow-up, no significant differences in mortality were observed between pericardial effusion groups (log-rank p = 0.46). Pericardial effusion volume was not associated with mortality when analyzed as a continuous variable (HR 1.00, 95% CI 0.996–1.01; p = 0.842), after logarithmic transformation (adjusted HR 0.91, 95% CI 0.76–1.08; p = 0.293), or in restricted cubic spline analyses. Conclusions: AI-derived pericardial effusion volume identifies a hemodynamic phenotype characterized by atrial fibrillation, pulmonary hypertension, and impaired right ventricular–pulmonary arterial coupling. Despite these associations, pericardial effusion volume does not independently predict long-term mortality after TAVI, suggesting that it reflects cardiovascular congestion and remodeling rather than a prognostically relevant phenotype.