Michael R. Minogue
Chairman, Chief Executive Officer and President at Abiomed
Thanks, Nicole, and good morning, everyone. In the first quarter of fiscal year 2023, Abiomed delivered a company record of $277 million in revenue, up 10% on a reported basis and up 12% in constant currency year-over-year with quarterly records across the U.S., Europe and Japan. Abiomed has achieved record revenue in five of the last six quarters despite ongoing headwinds with COVID variants, hospital labor shortages, supply chain constraints and most recently, contrast media shortages. Abiomed 2.0 has proven to be resilient because our technology and 24/7 hospital support addresses the growing epidemic of heart disease in multiple emergency patient populations in the cath lab and surgical suite. Within the quarter, we supported a record number of patients in the U.S. and had the second highest patient utilization in Europe and Japan.
We remain focused on innovation and strengthening clinical evidence, investing $41 million in research and development while achieving 23.8% operating margins. Our IP portfolio continues to grow with 1,487 patents and 1,610 patents pending. We ended the quarter with just over $1 billion in cash and maintained 0 debt. Additionally, this morning, we announced a new $200 million share repurchase program, a component of our capital deployment strategy upon completion of our anticipated closure of the prior $200 million plan. Our continued strong financial and operational performance is a result of our disciplined execution of our Abiomed 2.0 playbook which enables us to innovate breakthrough technology, advanced clinical research and support record levels of patients in this dynamic environment.
For today's call, I'd like to highlight the continued strength of our surgical products, driven by heart recovery with Impella 5.5. Second, we will review publications of clinical data that validate the benefits associated with Impella-supported PCI procedures. And finally, we will cover the progress we've made in our pursuit of classroom guidelines with multiple pivotal trials. Starting with surgery. In the U.S., surgical revenue grew 49% year-over-year, driven by a 66% increase in Impella 5.5. This revolutionary surgical heart pump with SmartAssist provides unique advantages for the chronic heart failure patient population suffering from cardiogenic shock.
As presented during our June investor call with Dr. Jane Wilcox and Dr. David D'Alessandro from Northwestern Memorial and Mass General Hospital, respectively, this game-changing technology has improved patient outcomes with 75% survival rate across all indications and 60% of patients returning home with their native hearts. These outcomes are particularly meaningful because these patients previously faced irreversible heart failure, which ultimately would have required a durable, implantable LVAD or heart transplant. I encourage all investors to watch this webcast on our Investor website. In Japan, we continue to find success with our controlled rollout of the Impella 5.5 with overwhelmingly positive surgical feedback.
We've witnessed survival rates and duration of support similar to that in the U.S. in the early stages of our product launch. We anticipate the expansion of this innovation to new sites and surgeons in Japan, setting a stage for heart recovery in surgery and protocols for the future. Turning to recent clinical data. RESTORE EF, a prospective multicenter study evaluating best practices in contemporary high-risk PCI practice, will be published later this month in [Indecipherable]. It was most recently presented as an abstract at a large Cardiology meeting. At their 90-day follow-up, study participants had a 29% relative improvement in their baseline LV -- left ventricular ejection fraction, an overall 76% reduction in New York Heart Association Class III and Class IV heart failure symptoms and an overall 97% reduction in Canadian Cardiovascular Society Class III or Class IV angina symptoms.
The RESTORE EF study combined with PROTECT 1, PROTECT II and PROTECT III FDA studies and multiple independent physician studies demonstrate definitive proof that Impella-supported high-risk PCI can lead to a more complete revascularization and considerable left ventricular ejection fraction improvement, which improves heart function and quality of life for the patients. AMI cardiogenic shock has one of the highest mortality rates in the field of medicine. These are patients sometimes showing up at the hospital, getting CPR and rush to the cath lab.
The survival rate has remained approximately 50% without Impella and associated best practices for the last 20 years. Impella technology is designed to not only improve survival but enable heart recovery. Impella best practices such as placing Impella pre-PCI show before the physician places stents, it's been developed by the recognized physician experts in the field of circulatory support and is published in multiple clinical studies over the last decade from the United States, Germany, Italy, Denmark and now Japan. In May, the International Journal of Cardiology published a meta-analysis of Impella pre-PCI versus post-PCI implantation in AMI cardiogenic shock.
This publication summarized 13 papers, totaling 6,810 patients and demonstrated a statistically significant lower mortality with Impella implantation before the PCI or the physician placing stents. Multiple Impella studies demonstrate greater than 70% survival with greater than 90% native heart recovery. Heart recovery after AMI cardiogenic shock improves patient quality of life and makes Impella one of the most cost-effective therapies in the CMS Medicare population as well as private insurance. Lastly, I'd like to highlight our progress towards advancing clinical evidence through multiple pivotal trials. We had a record quarter for patient enrollment for both PROTECT IV and STEMI DTU. Starting with PROTECT IV. In Q1, we rolled -- enrolled 91 patients. PROTECT IV is one of the most comprehensive studies ever done in the cath lab. This landmark trial will compare the benefits of an Impella-supported high-risk PCI versus high-risk PCI without Impella support.
Researchers will measure complete revascularization, improvement in patient quality of life and ejection fraction. For the STEMI DTU pivotal trial, we enrolled 45 patients in Q1. If successful, this trial could expand our indications into heart attack patients without cardiogenic shock, which represents a 200,000 patient population in the U.S. and four million patients worldwide that we do not treat today. I'm also excited to announce that in July, we received FDA IDE approval for RECOVER IV. This is an FDA randomized controlled trial comparing all-cause mortality of 30 days in patients with STEMI, cardiogenic shock with an Impella-based treatment strategy initiated prior to PCI versus a non-Impella-based standard of care treatment strategy.
Our teams have worked closely with the FDA to generate a protocol focused on exception from informed consent or EPIC, which we believe will help enroll patients in what has historically been a difficult patient population to enroll due to ethical and logistical concerns. The study details are posted in our earnings slides. Our current RCTs are built off a decade of prior studies and best practices with the goal of achieving Class I guidelines, the highest level of medical guidelines for high-risk PCI, cardiogenic shock and STEMI. If successful, we believe we'll be the only company in medtech with exclusive FDA approvals, a dedicated IP portfolio and Class I guidelines. Before concluding, I'd like to share a patient story. Ethan Bradshaw, 30 years old, is a state trooper from North Carolina. Motivated by a family history of heart disease, Ethan takes pride in living a healthy lifestyle.
He exercises several times each week and is a Brazilian Jiu-Jitsu instructor. On February 24, 2022, after experiencing chest pain and numbness in his arm at the gym, Ethan drove himself to Kernersville Medical Center. Upon arrival in the emergency room, Ethan collapsed. Medical personnel shocked Ethan multiple times and performed CPR before transferring him to Forsyth Medical Center in Winston-Salem, North Carolina. Ethan was in cardiogenic shock when he got to the catheterization lab with a reduced ejection fraction of 20%. So his heart was working about 1/3 of its strength. Dr. Samuel Turner implanted Impella CP with SmartAssist before the PCI and placing stents. After two days of support, Ethan's heart function showed dramatic improvement and the Impella was weaned and removed utilizing SmartAssist.
After three weeks in the hospital, Ethan returned home with his native heart. Ethan's heart function returned to normal, and in May, he returned to the line of duty. In July, five months after his heart event, Ethan and his wife, Makela, welcomed a baby boy, Ryan. Today, Ethan and Makela are visiting our headquarters in Danvers where they meet with employees and share their inspiring story of heart recovery as part of our Annual Patient Summit. In conclusion, at Abiomed, we are developing a new field of heart recovery and relentlessly pursuing better clinical outcomes and Class I guidelines. In Q1, we made progress toward our goals and remain focused on developing smaller, smarter, more connected devices, accelerating enrollment in key clinical studies and building commercial excellence as we continue through our fiscal year. I would like to thank our employees and customers for their commitment to advancing the standard of care and recognize our shareholders for their continued support.
I will now turn the call over to Todd Trapp, our CFO.