Karl Fengler

Dr. Karl Fengler


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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1 May 2024 in Hypertension
Verified
Journal Article
Open access
RTRaymond R. Townsend
Raymond R. Townsend
KFKeith C. Ferdinand
Keith C. Ferdinand
DKDavid E. Kandzari
David E. Kandzari
KKKazuomi Kario
Kazuomi Kario
FMFelix Mahfoud
Felix Mahfoud
MBMichael Böhm
Michael Böhm
BACKGROUND: The SPYRAL HTN-ON MED (Global Clinical Study of Renal Denervation With the Symplicity Spyral Multi-electrode Renal Denervation System in Patients With Uncontrolled Hypertension in the Absence of Antihypertensive Medications)trial showed significant office and nighttime systolic blood pressure (BP) reductions in patients with hypertension following renal denervation (RDN) compared with sham-control patients, despite similar 24-hour BP reductions. We compared antihypertensive medication and BP changes among prespecified subpopulations. METHODS: The multicenter, randomized, sham-controlled, blinded SPYRAL HTN-ON MED trial (n=337) evaluated BP changes after RDN compared with a sham procedure in patients with hypertension prescribed 1 to 3 antihypertensive drugs. Most patients (n=187; 54%) were enrolled outside the United States, while 156 (46%) US patients were enrolled, including 60 (18%) Black Americans. RESULTS: Changes in detected antihypertensive drugs were similar between RDN and sham group patients in the outside US cohort, while drug increases were significantly more common in the US sham group compared with the RDN group. Patients from outside the United States showed significant reductions in office and 24-hour mean systolic BP at 6 months compared with the sham group, whereas BP changes were similar between RDN and sham in the US cohort. Within the US patient cohort, Black Americans in the sham control group had significant increases in medication burden from baseline through 6 months ( P =0.003) but not in the RDN group ( P =0.44). CONCLUSIONS: Patients enrolled outside the United States had minimal antihypertensive medication changes between treatment groups and had significant office and 24-hour BP reductions compared with the sham group. Increased antihypertensive drug burden in the US sham cohort, especially among Black Americans, may have diluted the treatment effect in the combined trial population. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02439775.

1 October 2023 in Circulation: Heart Failure
Verified
Journal Article
Closed access
Karl-Philipp RommelKarl-Philipp Rommel
Karl-Philipp Rommel
SPStamatia Pagoulatou
Stamatia Pagoulatou
KKKarl-Patrik Kresoja
Karl-Patrik Kresoja
SRSebastian Rosch
Sebastian Rosch
ASAnne Rebecca Schöber
Anne Rebecca Schöber
PLPhilipp Lurz
Philipp Lurz
Background: Arterial stiffening contributes to hemodynamic derangements in heart failure with preserved ejection fraction (HFpEF). We sought to investigate the impact of renal denervation on pulsatile left ventricular loading in patients with HFpEF and hypertensive patients without heart failure (control). Methods: Patients underwent renal denervation for treatment of hypertension and were followed up at 3 months at a single center. A validated computer model of the arterial tree, noninvasive aortic flow curves, left ventricular volumes, and E/e′ as inputs were used to determine key parameters of left ventricular vascular load. Results: In comparison to controls (n=30), patients with HFpEF (n=30) demonstrated lower total arterial compliance (mean difference, −0.41 [95% CI, −0.72 to −0.10] mL/mm Hg), higher impedance of the proximal aorta (Zc: 0.02; 0.01 to 0.04 mHg·s/mL), premature wave reflections (shorter backward wave transit time normalized to ejection time: −3.5; −6.5% to −0.5%), and higher wave reflection magnitude (reflection coefficient: 7.3; 2.8% to 11.9%). Overall, daytime systolic (−9.2; −12.2 to −6.2 mm Hg) and diastolic blood pressures (−5.9; −7.6 to −4.1 mm Hg) as well as blood pressure variability (−2.0; −3.0 to −0.9 mm Hg) decreased after renal denervation. In patients with HFpEF, total arterial compliance (0.42; 0.17 to 0.67 mL/mm Hg) and backward transit time normalized to ejection time (1.7; 0.4% to 3.0%) increased; Zc (−0.01; −0.02 to −0.01 mm Hg·s/mL) and reflection coefficient (−2.6; −5.0% to −0.3%) decreased after renal denervation. This was accompanied by a symptomatic improvement in patients with HFpEF. Conclusion: HFpEF is characterized by heightened aortic stiffness and unfavorable pulsatile left ventricular load. These abnormalities are partly normalized after renal denervation.

18 November 2024 in Reviews in Cardiovascular Medicine
Verified
Journal Article
Open access
PDF file
PSParham Shahidi
Parham Shahidi
LMLuise Mentzel
Luise Mentzel
SBStephan Blazek
Stephan Blazek
DSDmitry Sulimov
Dmitry Sulimov
HTHolger Thiele
Holger Thiele
KFKarl Fengler
Karl Fengler
Venous thromboembolism presenting as deep vein thrombosis or pulmonary embolism (PE) remains to be an important cause of mortality and morbidity worldwide. Despite its significance and incidence, compared to many other cardiovascular conditions there are significant gaps in knowledge in many aspects of it, including its pathophysiology. A rare sequela of PE is chronic thromboembolic pulmonary hypertension (CTEPH). This complication has a poor outcome and data is scarce in this field. Many therapeutic approaches are based solely on clinical expertise, which can be explained by the complex and not fully understood pathobiology of this disease. Over the years, many theories have been proposed regarding its genesis. Although generally acute PE is accepted as a trigger for CTEPH, this condition is multifactorial and cannot be explained by recurring PEs only. By reviewing the current evidence, we have demonstrated that thrombus non-resolution in CTEPH is due to multiple mechanisms and predisposing factors including: inflammation, small-vessel disease, impaired angiogenesis, platelet dysfunction, coagulopathies, malignancy, impaired fibrinolysis, genetics and many other components. Based on the current evidence, we aimed to explain the pathophysiology CTEPH, PE and the connection between these two important diseases. Furthermore, we highlight the negative hemodynamic effects of CTEPH and PE on the right ventricle and its role in further exacerbation of these patients.

4 February 2025 in European Heart Journal Supplements
Verified
Journal Article
Open access
LMLuise Antonia Antonia Mentzel
Luise Antonia Antonia Mentzel
KFKarl Fengler
Karl Fengler
MOMehmet Oezkur
Mehmet Oezkur
PLPia Lanmüller
Pia Lanmüller
GTGuido Tavazzi
Guido Tavazzi
NWNikos Werner
Nikos Werner
Acute pulmonary embolism (PE) is a life-threatening condition caused by the thrombo-embolic obstruction of pulmonary arteries, which often leads to haemodynamic instability, right ventricular failure, and potentially death. Patients with massive or high-risk PE are particularly vulnerable and may not respond to conventional treatments, necessitating the implementation of mechanical circulatory support. Here, we discuss recent advancements in the diagnosis and multidisciplinary management of patients with high-risk PE and highlight the need for rapid and personalized treatment strategies.

15 August 2023 in Journal of the American Heart Association
Verified
Journal Article
Open access
SRSebastian Rosch
Sebastian Rosch
Karl-Philipp RommelKarl-Philipp Rommel
Karl-Philipp Rommel
SBStephan Blazek
Stephan Blazek
KKKarl‐Patrik Kresoja
Karl‐Patrik Kresoja
ASAnne Schöber
Anne Schöber
KFKarl Fengler
Karl Fengler
BACKGROUND: Renal denervation has proven its efficacy to lower blood pressure in comparison to sham treatment in recent randomized clinical trials. Although there is a large body of evidence for the durability and safety of radiofrequency‐based renal denervation, there are a paucity of data for endovascular ultrasound–based renal denervation (uRDN). We aimed to assess the long‐term efficacy and safety of uRDN in a single‐center cohort of patients. METHODS AND RESULTS: Data from 2 previous studies on uRDN were pooled. Ambulatory 24‐hour blood pressure measurements were taken before as well as 3, 6, 12, and 24 months after treatment with uRDN. A total of 130 patients (mean age 63±9 years, 24% women) underwent uRDN. After 3, 6, 12, and 24 months, systolic mean 24‐hour ambulatory blood pressure values were reduced by 10±12, 10±14, 8±15, and 10±15 mm Hg, respectively, when compared with baseline ( P <0.001). Corresponding diastolic values were reduced by 6±8, 6±8, 5±9, and 6±9 mm Hg, respectively ( P <0.001). Periprocedural adverse events occurred in 16 patients, and all recovered without sequelae. CONCLUSIONS: In this single‐center study, uRDN effectively lowered blood pressure up to 24 months after treatment.

9 August 2022 in Cardiology and Therapy
Verified
Journal Article
Open access
PDF file
KFKarl Fengler
Karl Fengler
Evidence from recent sham-controlled trials supports the use of endovascular renal denervation (RDN) to lower blood pressure in general as well as in treatment-resistant hypertension. According to recent studies, the effects of RDN are long lasting. Newer technologies using multipolar radiofrequency catheters and an additional ablation of the renal side branches as well as ultrasound with improved circumferential tissue penetration have made these advances possible. This has initiated a change of the perspective on RDN in clinical guidelines and has thereby set a cornerstone for a broader clinical application of RDN in the future.